By Richard Balmforth
KIEV (Reuters) - Ukraine geared up on Friday for an election which many commentators expect to cement President Viktor Yanukovich's rule, despite his jailed rival Yulia Tymoshenko calling on voters to stop an imminent "dictatorship".
Yanukovich's Party of the Regions and a union of opposition forces backing Tymoshenko were scheduled to stage their final public rallies later on Friday in the capital Kiev ahead of Sunday's poll for a new parliament.
The election takes place with the government unpopular because of tax and pensions policies and failure to stamp out corruption, and the former Soviet republic looking isolated after rows with the United States and the European Union over Tymoshenko, and with Russia over gas.
The export-oriented economy is vulnerable to external shocks such as falling demand for steel. The International Monetary Fund, whose loans could provide a financial cushion, froze lending in 2011 when Kiev balked at painful reform.
There is also the question of what judgment international observers will hand down after monitoring the election.
No opinion polls have been published since October 18, in line with an official information blackout.
But ratings before then showed the Regions with a firm lead over the joint opposition, which includes Tymoshenko's Batkivshchyna (Fatherland) party, and a new liberal party headed by world heavyweight boxing champion Vitaly Klitschko.
Commentators expect Yanukovich's pro-business Regions, which is bankrolled by wealthy industrialists and can draw on state and regional facilities and resources, to hold on to a majority in the 450-seat assembly.
In campaigning, the Regions have promised to make Russian an official state language alongside Ukrainian - a move aimed at winning back disenchanted supporters in Russian-speaking areas of the east and south.
The opposition warns that a Regions victory will usher in authoritarian rule and policies tailored to further enrich business "oligarchs" and Yanukovich's trusted inner circle of associates and relatives.
Tymoshenko, 51, a political firebrand in her heyday, on Thursday called on voters to throw out the Regions, warning Yanukovich could "establish a dictatorship and will never again give up power by peaceful means".
Much interest lies in whether the opposition, weakened by Tymoshenko's jailing, will be re-energized after the election.
Two-meter-tall Klitschko has pledged to work to stamp out endemic corruption in the country of 46 million. He and his UDAR (Punch) party, which has surged in ratings, represent a wild card in the poll.
He has turned his back on any alliance with the Regions and says he will side with the united opposition led by Arseny Yatsenyuk, a bespectacled, 38-year-old former economy minister.
But the fact Klitschko declined to sign a pre-election coalition agreement with Yatsenyuk-led forces has bred suspicion among the opposition.
Of the 450 seats in the single-chamber parliament, 225 will be filled through voting by party lists - where the voter casts a ballot for a party which presents a list of candidates.
The other half will be decided by voting for individual candidates on a first-past-the-post basis - a feature re-introduced by the Regions which is assumed to favor the party.
Other parties which have a chance of crossing the 5 per cent barrier to secure seats in parliament include Svoboda (Freedom), a nationalist party headed by Oleh Tyahnybok.
The Ukraine-Forward! party of Natalia Korolevska, formerly a Tymoshenko loyalist, describes itself as an opposition party. Korolevska has enlisted to her ticket soccer hero Andriy Shevchenko - the feet of Ukrainian sport to Klitschko's fists.
But the main opposition leaders says she is funded by industrialists who also back the Regions. They regard Ukraine-Forward! as a phantom party aimed at taking votes from them.
International monitors of the poll include a 700-member team from the Organization for Security and Co-operation in Europe (OSCE). The OSCE will deliver its verdict on Monday and Yanukovich will be eager to hear a positive assessment to improve his international image, if only because Ukraine takes over the chair of the human rights and security body in January.
Prime Minister Mykola Azarov, No. 1 candidate on the Regions ticket, said his government had worked hard to ensure that the election followed international standards in protecting the integrity of the vote and preventing systemic abuses.
But some Western voices have expressed reservations.
U.S. Secretary of State Hillary Clinton and EU foreign policy chief Catherine Ashton said this week the West was concerned at Tymoshenko's continued imprisonment, and at reports state resources were being used to promote Regions candidates.
(Writing By Richard Balmforth; Editing by Pravin Char)