In a statement released late Tuesday, the PQ described it as an "informal" meeting about financing and not a raid. According to the statement, investigators said they planned to speak with all parties about their structure and funding methods.
However, the Coalition party sent out a statement late Tuesday saying they had never been contacted by the anti-corruption squad to explain their finances.
Earlier in the day, the Liberal leader promised to publish 2012 income-tax returns and other financial details about himself and his wife on his party's website before Thursday's leaders' debate.
To help make his point, Couillard cited federal Liberal Leader Justin Trudeau's decision last year to disclose all his sources of income and said the move was well-received.
"I think it's both wise and justified that Quebecers know the state of the personal financial situation of not only the candidate, but also for their close family, notably their husband or wife," Couillard, who was in the private sector in 2012, told reporters during a campaign stop in Trois-Rivieres.
"It's a question of transparency," said Couillard, whose party is surging in the polls. "I hope the other party leaders will do the same."
But Parti Quebecois Leader Pauline Marois responded by saying she wouldn't follow suit, arguing the provincial ethics commissioner is "very satisfied" with the financial documentation she has already provided.
"The answer is no," Marois told a news conference north of Montreal when asked about Couillard's challenge.
"The ethics commissioner received all the documents that I was supposed to present and that my husband was supposed to present."
Marois, who reminded journalists how she made her 2011 income-tax return public during the 2012 campaign, accused Couillard of questioning the integrity of the ethics commissioner.
She also attacked Couillard for trying to create a diversion.
"Since he has nothing to propose in terms of ethics, he always finds side roads," Marois said.
Couillard's proposal appeared to be an attempt to put the spotlight on Marois's husband, Claude Blanchet, a wealthy businessman who once headed the Quebec government's investment arm.
In recent months, Blanchet has been at the centre of a controversy over his possible dealings with the province's largest labour federation.
It revolves around a 2009 wiretap played at the provincial corruption inquiry that hints at an arrangement between Blanchet and the Quebec Federation of Labour. The federation's Solidarity Fund invested just under $3 million with Blanchet's company, BLF Capital.
Marois and Blanchet, who have insisted they did nothing wrong, had been called to testify before a committee once the legislature resumed sitting March 11. But Marois called the April 7 election on March 5.
Questioned about his intentions, Couillard denied he was targeting Blanchet.
"No," he said. "It's only my view of today's demands on the concept of transparency, and the link of trust between the population and the people who want to govern Quebec."
Coalition Leader Francois Legault and the co-leader of Quebec solidaire, Francoise David, have both indicated they are open to the idea.
Couillard's proposition came as a new Internet poll suggested his party had seen a boost in popularity and had the support of 40 per cent of voters, compared with 33 per cent for the incumbent PQ.
The Leger Marketing survey of 3,692 Quebecers was conducted March 21-23 for Le Journal de Montreal.
The polling industry's professional body, the Marketing Research and Intelligence Association, says online surveys cannot be assigned a margin of error because they do not randomly sample the population like traditional telephone polls.
Leger said a traditional phone poll of the same scope would have a margin of error of 1.9 percentgae points, 19 times out of 20.
The poll also suggested that 31 per cent of Quebecers thought Couillard would make the best premier, while 25 per cent considered Marois the best choice.
On the ballot-box issue of Quebec independence, the survey found 77 per cent of those who had indicated they would back the Liberals believed a PQ majority government would hold a sovereignty referendum. However, only 17 per cent of respondents who said they would support the pro-independence PQ thought it would do so.
The PQ appears to have sputtered ever since it introduced Quebecor media baron Pierre Karl Peladeau as a star candidate.
Peladeau's high-profile jump into politics early in the campaign saw him pump his fist and vow to make Quebec a country, an idea that polls repeatedly suggest is opposed by a majority of Quebecers. Marois then spent the next couple of days musing about how a sovereign Quebec might operate.
Marois has since struggled to steer her campaign away from the sovereignty issue amid repeated attacks from Legault, who is anti-referendum, and Couillard, a staunch federalist.
On Tuesday, Marois criticized Couillard throughout her news conference and accused him of stoking referendum fears in the electorate.
"Mr. Couillard is trying to scare Quebecers because he doesn't have any subject matter to present about his platform or his team," said Marois.
In response to a question about Peladeau's campaign launch, Marois said she knew before the event that the media tycoon would make an impassioned call for independence.
"He simply made the statement that was pertinent and justified, and we had agreed on it together," she said.
The PQ also presented a challenge of its own Tuesday for Couillard on the issue of transparency when it filed a complaint with Quebec's electoral office.
Cabinet minister Pierre Duchesne said in a statement the PQ asked officials to investigate possible illegal financing by the Liberals.
Quebec's anti-corruption police unit searched Liberal offices last July and the companies of ex-party fundraiser Marc Bibeau in November.
Earlier this month, documents made public from the searches revealed the Liberals amassed more than $700,000 in contributions, including one event that generated $428,000. Duchesne said the electoral office has no record of a $428,000 fundraising activity.
Later on Tuesday, the PQ confirmed that Sylvain Tanguay, the PQ's director general, and Pierre Seguin, its director of finances and administration, had met "in an informal manner" with two detectives from the provincial anti-corruption squad in February and were asked about financing.
The party said in a statement it told the police it is funded by voluntary donations and records are kept. It also pointed out it had not been raided and no documents had been seized.
The PQ said it had kept the meeting confidential at the request of the anti-corruption but felt it needed to break its silence when it was raised by the media.
The Liberals were also targeted Tuesday by Legault, who warned Quebecers about the risks of electing a Couillard government.
He said Quebecers wasted six months debating the secularism charter and now electors have been cornered by the referendum issue.
"I accuse Philippe Couillard of surfing on this ... while having nothing to propose to Quebecers," said the leader of the right-of-centre party.
"I am concerned for the future of Quebec."
(With a file by Nelson Wyatt of The Canadian Press in Montreal)
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