Recently dismissed Polish interior minister Janusz Kaczmarek said that upcoming elections may lack credibility because the ruling conservatives planned to use the state apparatus to manipulate them.
'Today the prosecutors and the special services are a tool used to gain power,' Mr Kaczmarek told a news conference.
He added: 'If these tools are in their (the conservatives') hands, elections may be not completely fictitious but definitely manipulated.'
Mr Kaczmarek, previously an ally of Prime Minister Jaroslaw Kaczynski and his twin brother, President Lech Kaczynski, was sacked two weeks ago.
A series of scandals and rifts broke apart the prime minister's coalition with two small fringe parties earlier this month and he has agreed to call snap elections, probably in October.
The Kaczynski twins won elections in 2005 on a promise to weed out corruption and implement a moral revolution. Their critics accuse them of neglecting reforms and concentrating on expanding their power and discrediting political opponents.
The Anti-Corruption Office, created by the brothers to chase sleaze in politics, accused Andrzej Lepper, leader of a junior coalition party, of involvement in a corruption case.
No evidence against Mr Lepper has ever been presented and most commentators agree the accusation was an attempt to discredit Lepper and take over his voting support.
'The brothers may be supporters of free elections but they will use all methods to influence their outcome,' said Roman Giertych, leader of the far-right League of Polish Families, another coalition member.
The Kaczynskis sacked Mr Kaczmarek after blaming him for a leak that exposed the investigation against Mr Lepper.
Justice Minister Zbigniew Ziobro dismissed Mr Kaczmarek's criticism as part of the election campaign.
'These accusations have nothing to do with the truth,' he said.
Parliament reconvenes after a summer break on Wednesday and may vote on a motion to dissolve itself to trigger early polls.
