KIEV  - Ukraine's opposition and the party of President Viktor Yanukovych made a final bid for votes on Friday, the last day of campaigning before the country's tightly-contested weekend parliamentary polls.

Sunday's ballot to the Verkhovna Rada parliament has been marked by Western prodding of the authorities over the absence of the jailed opposition leader and ex-premier Yulia Tymoshenko who has been convicted for abuse of power.

But the opposition has refused to be demoralised and rallied in the closing stages around the intriguing candidacy of heavyweight boxing champion Vitali Klitschko -- a charismatic speaker who campaigns against corruption with his aptly-named UDAR (Punch) group.

The government meanwhile has vowed to conduct fair elections in the nation of 46 million -- which occupies the strategic edge between Russia and EU states -- with the help of monitoring cameras and the Internet.

"All these tales and stories about how the vote can be falsified -- this is simply impossible because of the technology," Prime Minister Mykola Azarov told reporters while inspecting the new equipment at a Kiev polling station.

"Without question, the elections will be fair," the close Yanukovych ally stressed.

Campaigning is banned on Saturday and all the factions are planning rallies later Friday to swing wavering voters.

The polls have given voters a chance to voice their frustration with a generation of leaders who had promised change in the 2004 Orange Revolution in which Tymoshenko -- her blond braid prominent on protest posters -- played a leading part.

Nearly a decade of subsequent infighting between government clans that came amid economic stagnation and wide-scale reports of abuses appear to be coming to a head in Ukraine just in time for Sunday's ballot.

The stain of corruption has also touched Tymoshenko -- who endured low popularity in her own premiership -- as her group struggles to secure second place against the strong reception awarded to the anti-graft campaign of Klitschko.

Yanukovych's lead with his Regions Party may be challenged after the election as the opposition mulls a long-discussed alliance and the ruling party relies on the shrinking Communist vote for support.

Tymoshenko's daughter Yevgenia read out an emotional letter from her detained mother on Thursday calling on Ukrainians "not to cast a single vote" for Yanukovych's ruling Regions Party.

"Chasing this mafia from power is not only the task of the opposition. It is a war against dictatorship and against injustice that requires the mobilisation of each of you," the letter added.

The letter came as US Secretary of State Hillary Clinton and top EU diplomat Catherine Ashton published an extremely rare joint appeal on the eve of the vote in which they called on Yanukovych to prove his democratic credentials.

"We are concerned about reports of the use of administrative resources to favour ruling party candidates and the difficulties several media outlets face," they said in a letter published in the International Herald Tribune.

"Important steps now have to be taken by the Ukrainian government to fulfil its full potential," the letter noted.

Klitschko for his part has been running a hectic schedule that has seen his towering figure appear at two or three different campaign events around Kiev every evening.

The national sports hero turned up at a football stadium on the edge of Kiev for a campaign event to support one of his party's local outsiders late Thursday.

Klitschko used the occasion to insist that he was concentrating on the parliamentary polls even as his adoring fans urged him to take on Yanukovych in 2015.

"As of today, the people's support is pushing us into the Rada," Klitschko said as chants of "President!" echoed in the crowd. "That is what we are working towards today," Klitschko said.