KIEV, Oct. 22 - President Petro Poroshenko's bloc holds a big lead ahead of Ukraine's election on Sunday while a rising populist party looks set to take second place, an opinion poll showed on Wednesday.

A surge in support for the Radical Party of populist Oleh Lyashko, the champion of government troops and scourge of super-wealthy oligarchs, threatens former Prime Minister Yulia Tymoshenko's chances of winning a seat in the new parliament, according to the survey by the Democratic Initiative Foundation.

Poroshenko's Solidarity party and its Udar ally, led by former boxer Vitaliy Klitschko, would take 20.5 percent of the vote while support for the Radical Party jumped to 8.6 per cent after a little over six percent a month ago, the survey said.

This is the first general election since Moscow-backed leader Viktor Yanukovych was ousted in February and Poroshenko wants a clear mandate to press his plan to end a separatist conflict and pursue integration with mainstream Europe.

With pro-Russian forces gone from parliament, Poroshenko should have no difficulty forming a pro-Western coalition with allies such as the People's Front party of Prime Minister Arseny Yatseniuk to press forward with Europe-friendly reforms.

But if the populist Lyashko makes a very strong showing, Poroshenko may have the awkward task of seeking the support of a politician who has been sharply critical of his peace plan and his contacts with Russian President Vladimir Putin.

The survey showed that only four of 29 political groups in the race would clear the five-percent threshold required to gain seats in the 450-member assembly.

One of the expected also-rans is Tymoshenko's Batkivshchyna (Fatherland) party, whose support slipped to 4.7 percent as Lyashko's Radicals rose in popularity.

Once a fiery public speaker, Tymoshenko, 53, was prime minister under former president Viktor Yushchenko and has been one of Ukraine's most popular leaders of the past 10 years.

An old adversary of Yanukovych, who narrowly defeated her for the presidency in 2010, she was subsequently jailed by him and was only freed when the "Euromaidan" protests against his rule took off last winter in Kiev.

But with the political landscape radically redrawn, she has failed to re-kindle mass support or win a sympathy vote.

Since losing heavily to Poroshenko for the presidency in May, she has fought a subdued campaign and seen key allies defect. If she fails to win a parliamentary seat on Sunday, it could mean her political eclipse.

Candidates' lists for almost all the main pro-Europe parties are studded with the names of war veterans and political activists, reflecting Ukraine's tumultuous past 10 months which have seen Russia's annexation of Crimea and the outbreak of separatist war in the east with the deaths of more than 3,700 people.

The survey said that 32 percent of the 2,025 people polled were undecided.

The election has been challenged by the pro-Russian separatists who vow to block voting in 14 districts in eastern regions and stage a separate election in early November.

The survey measured support only for candidates on party lists which will decide half the 450 seats on offer.
It did not cover the other half, which are decided by individual contests in so-called single-mandate constituencies.

Candidates in single-mandate districts are an unpredictable force since their support can often be bought by local power brokers or big business and their loyalties are often difficult to tie down.

But they generally tend to vote for the ruling elite and commentators said they expected this to be the case this time.

"In these elections, Poroshenko's people will win in the largest part of the single-mandate districts. The personal rating of the president - and he has about 40 percent support - will play a decisive role," said Taras Berezovets of Berta Communications, a political research institute.

Yanukovych's Regions Party, which formerly dominated the parliament, has virtually been extinguished as a political force. Its Communist allies also seem likely to find themselves without any representation in the assembly for the first time since independence in 1991. (rt/ez)