KIEV, October 31 (RIA Novosti) - Ukraine's prime minister, Yulia Tymoshenko, was formally registered on Saturday as a candidate in the presidential election due on January 17.

Tymoshenko was nominated last week by her Batkivshchyna (Fatherland) coalition at a rally on Kiev's Independence Square, the main venue of "orange revolution" protests against alleged ballot rigging, which swept President Viktor Yushchenko to power five years ago.

Opinion polls point to Tymoshenko, an ally-turned-rival to the current president, as a leading contender following Viktor Yanukovych, ex-premier and Yushchenko's opponent in the 2004 race.

Pollsters, however, say none of the candidates is likely to garner the 50% plus one vote required to avoid a runoff.

Other registered contenders include Supreme Rada Speaker Volodymyr Lytvyn, ex-defense minister Anatoliy Hrytsenko and Communist leader Petro Symonenko.

The incumbent leader is unlikely to win the vote as polls put his support in the low single digits.

Ukrainians look to the election to end several years of political infighting that has complicated decision-making in the country, which has been hit hard by the global recession.