The Kremlin is planning to rig the results of Russia's parliamentary elections on Sunday by forcing millions of public sector workers across the country to vote, the Guardian has learned.

Local administration officials have called in thousands of staff on their day off in an attempt to engineer a massive and inflated victory for President Vladimir Putin and his United Russia party. Voters are being pressured to vote for United Russia or risk losing their jobs, their accommodation or bonuses, the Guardian has been told in numerous interviews with byudzhetniki (public sector workers), students and ordinary citizens.

Doctors, teachers, university deans, students and even workers at psychiatric clinics have been warned they have to vote. Failure to do so will entail serious consequences, they have been told.

Analysts say the pressure is designed to ensure a resounding win for the United Russia party and for Putin, who heads its party list. The victory would give him a public mandate to maintain ultimate power in the country as "National Leader" despite being unable to stand for a third term as president in March.

In a televised speech yesterday Putin implored the nation to turn out and vote for United Russia, saying: "I count on your support." The president enjoys genuine popular backing but a spokeswoman for Golos, an independent organisation monitoring the elections, said "big pressure on voters across the country" was being used to balloon the result for United Russia.

"We are seeing a new phenomenon where voters are forced to get absentee ballots under threat of being sacked or being denied bonuses," she said. "People are then instructed to vote at their workplace where everything is tightly controlled." The spokesman said the pressure applied to private businesses as well as state-run enterprises.

Students have been told they risk the prospect of failing exams or being removed from courses if they do not vote for United Russia. Alexander, a journalism student at Oryol State University, said: "It's been made very clear that students who don't get absentee ballots and vote the right way could lose their place in the dormitory."

Anna, 31, a schoolteacher in Ulan Ude, said: "We were called to the staff room in my school about a month ago and asked to sign a formal declaration promising that we would vote for United Russia. I told them that I wanted to vote for another party, but they told me to sign it in such a manner that there was no way to refuse. They hinted I could lose my job."

A librarian in Buryatia region said she had been promised a premium on her salary if she voted for United Russia.

The Kremlin insists Sunday's elections will be free and fair, despite inviting only 400 international observers to monitor the poll, which is taking place in 95,784 polling stations across the world's biggest country. This month the Organisation for Security and Cooperation in Europe's office for Democratic Institutions and Human Rights (ODIHR) cancelled its mission to Russia after Moscow refused to give its experts visas.

Asked whether the Kremlin was planning to manipulate Sunday's election Vladimir Churov, the head of Russia's central election commission, told the Guardian: "They will be the most free, most transparent, and most suitable elections for citizens."

However, while state television has made no mention of electoral violations, websites and independent newspapers outside state control are seething with reports of attempts to pressure voters to turn out for United Russia.

Bloggers on Russia's most popular social networking site, Livejournal, have posted numerous accounts of intimidation. One in Murmansk wrote that he was told that if he didn't vote for United Russia "the management would get it in the neck".

Another in Yekaterinburg wrote: "Today my wife came home in shock. As the boss of a state company she has been told that all her workers living in different parts of town must take absentee ballots and go to vote in Kirovsky district. She has to go and sit all day on December 2 and call round everyone in her collective. Then she has to provide a list of who has voted." She then received a directive warning her to add anybody who didn't vote for United Russia to a list, and later those people would be "called to the office" of the local administration.

The Kremlin has cast Sunday's State Duma vote as a referendum on Putin. Although Putin is obliged to step down as president next May, a landslide victory may be used to legitimise his return to power, possibly as early as the summer.

The president's personal popularity remains high. But support for United Russia is less solid. Independent experts say the party's true ratings are around 35% - well below the 55% figure suggested by state-controlled opinion polls.

In a leak to Russian media this week, one senior election official said that regional governors had been told to deliver at least 65% of the vote for Putin's party, an "unrealistically high" total that could be achieved only through electoral fraud and by compelling people to vote.

"The elections are going to be falsified," said Mikhail Delyagin, an economist and the director of Moscow's Institute on Globalisation Problems. "The elections that took place in the Soviet Union were less falsified than this one."

He added: "All those who depend on state salaries have been forced to go and vote. This means workers on all levels of state power working for local government, all the military, and those who are in prison or psychiatric hospitals. Of course people have the possibility to lie. But there is enormous psychological pressure."

Regional election workers would also stuff ballot boxes - as they had done on previous occasions - boosting United Russia's vote by about 20%, he estimated. These results could be refined still further by using the election commission's central computer. "You can falsify as much as you want. But the result must be truthful-looking," he said.

Putin's decision to associate himself with United Russia's election campaign - and to stand as a candidate at the top of the party's federal list - has contributed to the scale of the fraud, analysts said.

"The scale of pressure is due to nervousness within the Kremlin administration since it announced that this is no longer a parliamentary election but a referendum on Putin," Fyodor Lukyanov, editor-in-chief of the journal Russia in Global Affairs, said. Lukyanov said he believed the amount of fraud on polling day would be small. "This is normal in contemporary advanced authoritarian systems. They are smart enough to organise the vote in quite a proper and correct way," he said.

Coercing people in advance was a more effective tactic, he added. "The consequences [of not voting for Putin] are not perhaps as bad as they promise. But there is psychological pressure, of course. I had thought Russian authoritarianism was much softer. We will see."

The squeeze on public sector workers follows numerous rule changes by the Kremlin to Russia's electoral system. Under a new law, all parties need 7% of the vote to enter parliament - up from 5% last time. Additionally, several democratic opposition parties have been banned from taking part. The Kremlin has also abolished constituency voting - in effect wiping out the last critics from the current Duma. It has also scrapped minimum turnout.

Critics allege that United Russia has received disproportionate media coverage on state-controlled TV while opposition figures have been blacklisted. Putin's speech at a US-style election rally in Moscow last week, in which he denounced Russia's opposition as "jackals", got 16 minutes on the main evening news.

"These elections are a farce," said Vladimir Ryzhkov, an independent MP banned from standing. The Kremlin liquidated his Republican party earlier this year, claiming it didn't have enough voters. "I call it a Kremlin biathlon. In a normal biathlon the sportsmen shoot at targets, but in the Kremlin biathlon, not only do the sportsmen shoot at their targets, but the judges shoot at the sportsmen," Ryzhkov said. "Half of Russia's politicians can't run. It's selection before election."

Yesterday the central election commission dismissed suggestions that public sector workers had been told they had to vote. Churov told the Guardian he regarded the allegation as a "provocation" put about by the opposition. "This is just propaganda," he said.

He also claimed it was "not possible" to manipulate results stored in the commission's central computer, nicknamed Elections. Voters could find out the result at their individual polling station by dialling 5503 on their mobile phones, he said.

It wasn't Russia's fault that the OSCE had cancelled its mission, he added. "I was waiting for the head of the ODIHR in Moscow. But instead he flew off to Washington," Churov complained.

Kremlin aides openly acknowledge that their aim is to push smaller parties out of parliament. "We have moved towards the purification of the legislature," said Putin's deputy spokesman, Dmitry Peskov.

Case studies

Ivan, power station worker, Ufa
Every worker is being forced to take an absentee ballot and instructed to vote at one particular polling station with the rest of the workforce, all together for United Russia. It will be very easy for them to count who has turned up, who hasn't, and how they've voted. On every shift, in every department we are constantly being told that if you don't comply you'll get the sack.

Yelena, nurse, Ulan Ude
Every week we have a work briefing in our poliklinik [doctor's surgery]. They are always pressing on us to vote for United Russia. The head doctor ... says that if we don't vote for United Russia we won't get our Putin pribavki [federal funds added to nurses' salaries].

Dasha, 19, student, Moscow
I was hanging out with my friends in Novogireyevo [in Moscow] near the metro. There were six of us. We were approached by a car. A young man came out. He started talking to us about the elections and said if we wanted to vote for United Russia we could get 500 roubles. I didn't agree but four of my group did. They filled in some kind of form - name, surname and passport data. They were given the numbers of polling stations where they should go and vote and get the cash.

Anastasiya, 40, librarian, Buryatia
There was a meeting in the village where all doctors, teachers, nurses were gathered by the culture department of the local government ... The doors were closed and we were like hostages. We were told write a declaration saying "I, name and surname, pledge to vote for United Russia and these are my passport details ..." We were told that if United Russia got a high percentage in the village we would get a bonus on our salaries.

Natalia, 29, Novosibirsk
Some activists from United Russia came to my home. They asked if I was going to vote for their party. I said no because I don't agree with its ideology. And they replied, Well, look, there's blacklist of people who aren't voting for United Russia. We know where you live and we are going to add you to that list.

Masha, student, Vladimir
We were told - you study in a state university, so you should vote for the state party. I don't know what to do. I wanted to vote for another party. But it was so difficult to get into university, I don't want to be thrown out.

· Some names have been changed