Oct. 7 (Bloomberg) -- Poland's presidential race on Oct. 9 may fail to produce a victor, forcing the two parties that won last month's general election to delay forming a coalition as their candidates vie for the post, opinion polls show.

Citizens' Platform Chairman Donald Tusk and Law & Justice's Lech Kaczynski are running for head of state in a field of 13 candidates. They may vie in a second-round runoff Oct. 23 as neither has the support of a majority of voters, according to an Oct. 1-3 survey by the Center for Public Research.

The parties deferred talks on the makeup of the cabinet and their economic program until after this weekend's election because of differences over tax cuts and state asset sales. Kaczynski's twin brother Jaroslaw, chairman of Law & Justice, says he will not seek to become prime minister if his brother wins the presidency.

``It is difficult to expect a friendly coalition when competition between presidential candidates overshadows the whole process,'' said Marcin Mroz, chief economist at Societe Generale in Warsaw. ``It may take a couple of weeks before we get some firmer coalition program.''

Law & Justice won 155 seats in the Sept. 25 election for the 460-seat parliament. Citizens' Platform took 133 seats. The parties pledged in February to work together.

Tusk, 48, is leading the race with 40 percent support, the Center for Public Research survey of 1,026 potential voters showed. Kaczynski has 35 percent backing, according to the poll, which had a margin of error of 2.5 percent.

Kaczynski Brothers

Support for Kaczynski, the mayor of Warsaw, has risen 10 percentage points since August as his party came from behind to win the parliamentary elections. His brother, Jaroslaw, the party chairman, avoided a lead role in coalition talks and nominated Kazimierz Marcinkiewicz for prime minister.

``A relatively small gap in voter support for the two candidates may further sharpen the election campaign and leave a deep rift, making cooperation between Law & Justice and Citizens' Platform difficult,'' said Pawel Kowalski, chief economist at DZ Bank in Warsaw.

Half the Poles registered to vote are concerned the Kaczynski brothers may assume the offices of prime minister and president, according to a survey by the TNS OBOP research center for Polityka weekly, published Oct. 5.

The parties won the general election on promises to increase salaries and reduce the budget deficit enough to adopt the euro by 2009. The average Polish wage of $757 a month is one-fifth that of the European Union. Citizens' Platform wants greater tax cuts than Law & Justice, which would protect social programs.

Zloty Weakens

The zloty has declined 1.5 percent against the euro since the election, paring a 5 percent gain in the first nine months of the year on optimism Citizens' Platform would win. The yield on the 5.75 percent five-year benchmark government bond has risen 36 basis points in the two weeks since the election, its price dropping 1.6 percent to 103.82 per 1,000 zloty face value.

The presidential campaign is the first in the nation's 16-year post-communist history to take place amid coalition talks. The president represents Poland abroad, is head of the army and can veto laws. His veto can in turn be overruled by parliament.

``No one has ever tried to form a coalition government at the same time as there is such a sharp competition for the president's office,'' Tusk said at press conference yesterday in Warsaw.

The Kaczynski brothers, born in Warsaw in 1949, are lawyers who joined the opposition in the 1980s and are known for their anti- communist views. Their manner is praised by supporters as direct and criticizes by opponents as aggressive.

`Moderate, Tolerant'

The twins founded the Law & Justice party in 2001, the same year Citizens' Platform was formed, on a pledge to fight corruption that party leaders say is still rampant in Poland.

The party favors outlawing the Democratic Left Alliance, which has governed since 2001 and is the successor to the Communist Party. Law & Justice also seeks more power for the president.

``I am confident that the decision is in the hands of Poles who want their country to be balanced, moderate and tolerant and if so, I will win,'' said Tusk, a history graduate from the northern port city of Gdansk.

To contact the reporters on this story: Dorota Bartyzel at dbartyzel@bloomberg.net Katya Andrusz at kandrusz@bloomberg.net

Last Updated: October 6, 2005 19:11 EDT