Over 30 million Poles are entitled to cast their ballot on Sunday in a tight vote to choose either the twin brother of the late Polish president or the interim head of state as their new leader.

The first round of early elections, forced by President Lech Kaczynski's death in the April air crash in western Russia, was held on June 20. It was narrowly won by acting president Bronislaw Komorowski (41.54%), a pro-EU, moderate member of the governing Civic Platform party.

His main opponent Jaroslaw Kaczynski, an ex-prime minister who now leads the conservative Law and Justice party, was second with 36.46% of the vote.

A total of 25,774 polling stations, including 263 abroad and five on Polish-flagged ships, will open on Sunday. The turnout forecast is some 54%.

Numerous surveys, conducted before the elections, were unable to clearly predict the outcome as the margin between the two candidates has shrunk from some 10% to figures below the error margin limit in the past week.

Four days ahead of the elections Komorowski enjoyed a 52.1% support, with Jaroslaw Kaczynski scoring 41.6%.

The GfK Polonia research, published on Friday evening, shortly before the no-campaigning day was due to start, puts Kaczynski as winner with 49% of the vote, only 2% ahead of Komorowski.

A poll by MillwardBrown SMG/KRC, published a day later, puts Komorowski ahead with 51%, while Kaczynski trails with 44%.

The country's Fortuna betting company say most poles see Komorowski as the clear favorite to win, with almost 80% of all gamblers betting for his victory. The largest bet was about $3,000.

The odds are 1 to 1.25 for Komorowski and 1 to3.2 for Kaczynski

WARSAW, July 4 (RIA Novosti)