Then Ukrainian Prime Minister Yulia Tymoshenko seen in this 2010 file photo. Picture: Konstantin Chernichkin/Files

Kiev - Ukraine's glamorous but polarising ex-premier Yulia Tymoshenko was triumphantly released from prison during the pro-Western uprising in Kiev but is now a longshot in Sunday's presidential ballot due to mistrust of the corruption-stained old guard.

The most influential female politician to have emerged from the former Soviet Union appears to retain an unquenched thirst for office despite nearly three years behind bars on abuse of power charges drawn up by allies of Viktor Yanukovych, the pro-Russian who narrowly beat her in the 2010 vote and whose regime was toppled after bloody street fighting in February.

The fiery blonde 53-year-old - her braided hair wrapped over her head in a peasant style evoking her Ukrainian nationalist roots - often provokes either unabashed hatred or devotion both at home and abroad.

Her desire to see Ukraine folded more tightly into Europe has won her the sympathies of such world leaders as German Chancellor Angela Merkel and successive administrations in the White House.

But her detractors see the woman who made a fortune in murky post-Soviet state privatisations as an unscrupulous opportunist who lacks ideals and shifts alliances to best suit the latest political winds.

Russian President Vladimir Putin seemed to only confirm suspicions of Tymoshenko's most bitter detractors by describing his supposed rival in March as the one politician in Kiev with whom he could engage in “constructive work”.

Tymoshenko - confined to a wheelchair due to chronic back pain she allegedly developed in prison but that some diplomats privately acknowledge may be faked - discovered firsthand how the mood in Kiev has shifted against Ukraine's old guard only hours after her February 22 release from jail.

She was whisked to Kiev's main protest square on the very day of Yanukovych's ouster and bundled on stage for what was meant to be a triumphant appearance marking her grand and unlikely return.

But many in the crowd of more than 50 000 - having just witnessed dozens of pro-Western unarmed teenagers slain by police snipers in Ukraine's worst bloodbath since World War II - responded with jeers that would have seemed unimaginable during the dramatic 2004 pro-democracy Orange Revolution that had made her career.

And her high-profile attempt to act as peacemaker in Kiev's deadly confrontation with eastern Ukraine separatists backfired in April when rebels occupying government buildings in Donetsk refused to receive her for talks.

Tymoshenko is expected to win as little as six percent of the vote in Sunday's poll that may hand her pro-Western rival Petro Poroshenko victory in the first round.

Tymoshenko's steely resolve initially won her comparisons to the late British prime minister Margaret Thatcher. But most have since dropped the “iron lady” moniker and refer to her simply as “vona” - the Ukrainian word for “she” that underscores her seemingly permanent presence in politics.

The nationalist Batkivshchyna (Fatherland) party leader was raised by a single mother in the mostly-Russian speaking industrial city of Dnipropetrovsk.

But she now refuses to speak Russian in public and is a fervent supporter of Ukraine's membership in the Cold War-era NATO military bloc.

Tymoshenko first rose to prominence as head of a gas utility and became a deputy prime minister under the presidency of Leonid Kuchma in 1999.

She was fired from the post after the two had a public falling out - a theme that would repeat itself on several occasions in Tymoshenko's political career.

Tymoshenko was then also briefly imprisoned on gas smuggling charges that were later quashed. But the incident saw some start referring to her as the “gas queen”.

She returned to prominence during the Orange Revolution that first tried to shake Kiev's powerful Kremlin links.

That uprising eventually forced the annulment of elections initially awarded to Yanukovych - a man who would soon make his own unlikely political comeback.

Tymoshenko became prime minister under Orange co-leader Viktor Yushchenko. But both she and Poroshenko - then a member of the pro-Western government's national security and defence council - lost their cabinet seats less than a year later after failing to get along.

Her bitter defeat to Yanukovych in 2010 was followed by a string of criminal enquiries and a seven-year imprisonment on abuse of power charges both she and Western countries denounced as a case of selective justice. - AFP