QUEBEC - It was meant to be a powerful symbolic moment: Quebec's opposition parties, wearing white scarves outside the legislature Wednesday, demanding a public inquiry into corruption.

But one of the opposition parties failed to attend.

The Parti Quebecois, with the support of the one-member Quebec Solidaire and a pair of Independent legislators, announced they would be tabling a parliamentary motion demanding an inquiry.

They did so while clad in white scarves. There has been a deafening demand for an inquiry into corruption in the province's construction industry -- but the Liberal government of Jean Charest has refused to call one.

With that refusal, and with stories about questionable fundraising practices by the Liberals, Charest's popularity has taken a steep nosedive in recent months.

"I'm appealing to Mr. Charest's sense of honour," PQ Leader Pauline Marois said Wednesday. She explained the choice of clothing accessory by describing white as the colour of purity and light.

Still, the Action democratique du Quebec was a no-show at the event.

While ADQ Leader Gerard Deltell said he supports the idea of an inquiry, he cast Wednesday's tactic as the first step in something more nefarious: a power-grab by the PQ.

Deltell said he believes the PQ is trying to orchestrate a putsch that would topple the Charest government.

Marois, in recent days, has mused that she would be willing to replace the Liberals. She notes that, with only a thin parliamentary majority, the Liberals could be replaced if they lost a few members.

Deltell suggested Wednesday's announcement -- that there would be a vote in the legislature on an inquiry -- was aimed at pressuring legislators and sowing dissension in the Liberal ranks.

"Madame Marois smells the blood of power," Deltell said.

"And that's not the kind of politics I want to do."

The gambit also caused a contretemps with the Speaker of the legislature. He ordered opposition members to remove their scarves to maintain decorum in the chamber, and they did.