MONTREAL—With the Parti Quebecois having yet to release its economic plan, the Liberals took to the assault before Sunday’s debate to calculate the weight of the promises made by Pauline Marois and her troops.

According to Liberal Finance Minister Raymond Bachand, the figure is an eye-popping $3.6 billion.

“Having omitted to cost out their promises and spending before the debate is a lack of transparency and is disrespectful towards Quebecers,” said Bachand, hours before the province’s political leaders took to the podium on Sunday.

Holding the unusual press conference where the Liberal candidate used his perch as head of finances, Bachand defended his actions and repeated that the Liberals were not panicking despite poll after poll showing the party slipping rapidly.

A Leger Marketing survey on Friday found the Liberals barely holding onto official opposition status against the upstart Coalition Avenir Quebec. The PQ was solidly in majority territory in the sample, despite ceding some ground to Francois Legault’s CAQ.

According to Bachand, the PQ is proposing a $1 billion tax on investments and savings, something which he warned could impact the economy and the province’s future prosperity.

Stating that his numbers were firm and not based on hypothesis, Bachand claimed that the PQ’s scheme to repatriate unemployment-insurance would cost $800 million; abolishing the health tax would cost $1 billion; eliminating the tuition increase would cost $380 million; and Marois’ plan to create 15,000 new daycare spots would cost $200 million.

All the expenses, Bachand claimed, would cost Quebecers $10.6 billion over a PQ mandate.

“When you make these kinds of exaggerated populist promises, you need to find a way of financing them afterwards,” said Bachand, criticizing Marois for not putting in place a plan to control the province’s debt.

On the campaign trail, Marois had estimated her promises at $1 billion.

“We may have underestimated some expenses,” quipped Bachand, stating that his office couldn’t calculate the impact on tax credits.

On Friday, the Liberals released a $3.7 billion spending plan over the next five years.

Released the same day, the CAQ’s $3.8 billion economic plan called for a capital gains tax hike along with a $1 billion reinvestment in education and a $600 million increase to health spending. The plan would be funded by axing a number of Quebec institutions, including the province’s school boards.

The Liberal candidate for Outremont, Bachand is the party’s main lieutenant in the Montreal area.

--with files from The Canadian Press.