Quebec's Liberal government won't force Laval mayor Gilles Vaillancourt to resign over allegations of questionable campaign contributions, premier Jean Charest said Wednesday.

The opposition Parti Québécois is demanding Vaillancourt be suspended from the mayor's office, in the wake of explosive allegations  that have surfaced in the last two days, suggesting he offered two political candidates white envelopes containing cash.

'It's a serious matter. I think that the mayor must think twice about the right way to do things.' —Liberal justice minister Jean-Marc Fournier

"What we've learned in the last 48 hours strikes directly at the heart of our democratic system," said PQ justice critic Bertrand St-Arnaud. "The government should, at least, ask the mayor to leave his office temporarily."

The PQ also wants Laval – Quebec's third largest city – to be placed under provincial trusteeship until a police investigation is complete.

Charest waded into the debate Wednesday, telling national assembly members the legislature isn't a kangaroo court, and he wasn't going to suspend Vaillancourt.

But the embattled Laval mayor should be asking himself grave questions, because "it's a serious matter," said Liberal justice minister Jean-Marc Fournier. "I think that the mayor must think twice about the right way to do things."

Vaillancourt has categorically denied all accusations, and on Tuesday threatened legal action against both politicians who went public with their envelope stories.

In an exclusive interview with CBC's French-language service, Bloc Québécois MP Serge Ménard revealed Vaillancourt tried to offer him $10,000 in cash during a provincial byelection campaign in the Laval region in 1993.

Liberal MNA Vincent Auclair shared a similar tale, claiming that in 2002 Vaillancourt tried to give him a white envelope, which he refused.

Charest said he believes Auclair.