Polish Prime Minister Donald Tusk is facing calls to resign over reports published Sunday that his interior minister cut a deal with the head of the central bank to stay in power.
The secret recording allegedly features a conversation in which Interior Minister Bartlomiej Sienkiewicz tries to convince central bank chief Marek Belka to support government financial policy in return for the resignation of then finance minister Jacek Rostowski.
"In this situation, excuse me, the decommission of the minister of finance is essential," Belka is quoted as saying in the recording posted on Wprost magazine's website.
"Next there will come a new minister -- I don't have to tell you who that will be... We will do whatever is necessary to prevent" the opposition winning the next election, says the recording, allegedly taken in a restaurant in Warsaw mid last year.
"But that must not happen later than eight months before the elections," Sienkiewicz responds.
Rostowski was fired in November after six years as finance minister and replaced by Mateusz Szczurek, a 38-year-old economist from ING bank.
Poland's central bank denied any deal was struck, saying Belka's comments were "taken out of context" and that the recording was "manipulated to give the impression that the governor had exceeded his rights, which never took place".
But the allegations that one of Tusk's ministers sought help from the central bank to keep the opposition out of power has led to calls for him to step down.
The crisis comes at a crucial time for Poland as it grapples with security concerns sparked by the Ukraine crisis.
Tusk's ruling Civic Platform party is also facing rising voter dissatisfaction -- last month it won the European Union parliament elections by less than a percentage point.
"The only possible solution is the immediate resignation of the government," said Mariusz Blaszczak, a deputy for the opposition Law and Justice party.
Tusk has called a press conference to address the allegations on Monday afternoon in Warsaw.
"It's an unpleasant case and I'm not ignoring it," the prime minster posted on Twitter on Saturday.