* Govt faces no-confidence vote after corruption allegations * Junior govt member leaves talks, does not signal support
* Opposition needs majority vote to dismiss cabinet
(Adds details, more party comment, markets)
PRAGUE, Dec 20 (Reuters) - A junior coalition partner walked out of Czech government talks on Monday, the day before a no confidence vote in the centre-right cabinet. The three-party coalition's smallest member, Public Affairs, had not openly backed the cabinet since the main opposition party initiated the no-confidence motion last week after corruption allegations involving the Environment Ministry.
The allegations have led to the environment minister's resignation and sparked the first serious rift in the coalition since the parties swept a May election on pledges to cut budgetary deficit and fight graft.
Coalition leader Civic Democrats and conservative party TOP09 have said they would support the government in the Tuesday no-confidence vote but without Public Affairs they would not have a safe majority to vote down the motion.
The three parties hold 118 seats in the 200-seat lower house. Public Affairs has 24 seats, and could still abstain from the vote, which would cause the no-confidence motion to fail.
The two opposition parties in parliament, led by the centre-left Social Democrats, have a combined 82 seats, leaving them short of the 101 votes needed to dismiss the cabinet.
Prime Minister Petr Necas said after the talks ended that he was open to more discussions with Public Affairs.
"Of course, we are ready to communicate, there is no doubt about that," he told reporters.
Public Affairs has demanded the resignation of the police president and recognition for the whistle-blower who informed the media about attempts to manipulate tenders at the state environment fund, under the Environment Ministry.
Party officials in the talks were not available for comment. Deputy chairwoman Karolina Peake, who was not at the meeting, declined to comment. A spokeswoman said it was uncertain if the party would make a statement on Monday evening.
Fighting widespread corruption was the main vote winner in May for Public Affairs. The party has refused to declare support for the cabinet despite two other coalition meetings since Friday.
Environment Minister Pavel Drobil, a member of Necas's Civic Democrats, resigned last week. He denied any wrongdoing.
The rift came after the government, which has made fiscal reforms and fight against graft its main priorities, won parliamentary approval for the 2011 budget and prepared to draft pension and healthcare changes needed to keep spending under control in the years ahead.
Czech fiscal plans have won praise from investors this year and ratings agencies have raised the Czech outlook.
The crown <EUCZK=> held steady on Monday even as other central European currencies fell, but trades near a five-month low at 25.26 to the euro. (Reporting by Robert Mueller, writing by Jason Hovet; editing by Ralph Boulton)