By Adam Easton
BBC News, Warsaw
Polish MPs are to vote shortly on a motion whether to dissolve parliament and hold elections two years early.
The prime minister wants to root out ex-communist officials
The country's three largest parties, including the government, have said they will vote in favour of the motion.
The vote was scheduled after the ruling coalition collapsed last month. That left the party of PM Jaroslaw Kaczynski with a minority in parliament.
It appears likely that the necessary two-thirds of MPs will vote for an early election.
If that happens, the Polish President, Lech Kaczynski, must select a date for elections within 45 days. He says he favours 21 October.
Mr Kaczynski's twin brother Jaroslaw, the prime minister, has said he believes the voters will re-elect his conservative Law and Justice party.
In his party's favour is a booming economy and rapidly falling unemployment.
According to surveys, the prime minister's main rivals are the same party as two years ago, the centre-right but rather more economically liberal Civic Platform. It will be hoping that Mr Kaczynski's zealous drive to settle old scores with former communists and his methods of tackling crime and corruption will turn people against him.
In recent weeks the government has faced accusations, which it denies, of abusing the country's secret services to spy on its opponents.