The possibility of a third sovereignty referendum dominated the Quebec leaders' debate Thursday, as a combative Pauline Marois sidestepped what has become the central issue of the campaign.

The Parti Québécois Leader insisted that the April 7 election is not about a referendum, but about electing a government. Ms. Marois again refused to say whether she would hold such a vote if re-elected, but she said a third referendum would not come as a surprise.

"This won't be done secretly. You know all too well that it won't be done in the middle of night either. Let's calm down here," Ms. Marois said in deflecting the criticism of her referendum agenda. "A referendum won't be done like the night of the long knives against our will," she added in reference to the 1981 constitutional deal negotiated in the absence of then-PQ premier René Lévesque.

Story continues below advertisement

Liberal Leader Philippe Couillard accused the PQ Leader of wanting to fool Quebeckers into believing that there won't be another vote on sovereignty.

"Don't try and make us believe that you won't try and create the fights [with Ottawa] … to hold a referendum. We don't believe you," Mr. Couillard fired.

Unfazed, Ms. Marois mounted an aggressive charge of her own.

"No, there will not be a referendum until Quebeckers are ready to hold one," Ms. Marois said. "Mr. Couillard is trying to have us forget the Liberal years in power by saying this election is about a referendum. It is not."

Story continues below advertisement

The fiery exchange turned on the other hot-button issue of the campaign, the adoption of a secular charter that would ban the wearing of overt religious symbols in the public service.

Mr. Couillard was taken aback when Ms. Marois accused him of wanting to tear up the charter of Quebec values if the Liberals form government.

"How many women will lose their jobs?" Mr. Couillard asked, referring to Muslim women who wear the veil in the public service.

"The only woman I know who was fired was Fatima Houda-Pepin," Ms. Marois responded, blindsiding Mr. Couillard by referring to the former Liberal MNA who was excluded from the caucus after condemning Mr. Couillard's strong opposition to the secular charter.

Story continues below advertisement

Despite having threatened to attack each other's integrity, the leaders were on their best behaviour when it came to debating corruption and collusion in the awarding of government contracts. All refrained from making personal attacks.

Mr. Couillard was placed on the defensive for having negotiated a job in the private health sector while he was health minister just before quitting politics in 2008.

And Ms. Marois was forced to defend herself against a potential conflict of interest with the recruitment of Pierre Karl Péladeau, who holds the controlling interest in 40 per cent of the province's media through his holdings in Quebecor Media.

But both insisted that they will abide by the code of ethics and follow the recommendations of the Ethics Commissioner as he oversees the business interests of newly elected members.

Story continues below advertisement

In heated exchanges on the economy, the first theme of the debate, the leaders quickly got bogged down in contradictory numbers on how many jobs were created and where the government should invest. Ms. Marois came under attack for investing tens of millions of dollars to explore fossil fuels on Anticosti Island without having any idea of the level of oil reserves in the area.

"I am the only here who has created real jobs," Coalition Avenir Québec Leader François Legault, a former businessman, said. "Have you ever created a single job?" he asked Mr. Couillard.

The former Liberal regime headed by then-premier Jean Charest returned constantly to haunt Mr. Couillard, who had difficulty outlining his economic plan as he fended off charges of mismanagement.

On social issues, Québec Solidaire Leader Françoise David took the PQ Leader to task over her handling of the elderly. Ms. David positioned herself as the defender of the poor and underprivileged, denouncing cuts in health and social services.

But CAQ Leader accused his opponents of lacking the courage to cut spending and slash government bureaucracy as he championed eliminating unnecessary spending.

Story continues below advertisement

The CAQ had the most to lose in the debate as the party struggles to win back support of voters polarized over the referendum and charter issues.