BELOEIL, Que. -- The Constitution will not be reopened just to discuss the abolition of the Senate and that's something NDP Leader Tom Mulcair knows perfectly well, his Bloc Quebecois counterpart said Thursday.

Speaking at a campaign event, Gilles Duceppe said the Constitution has a "double lock" on it, and cracking it open to talk about the Senate is a non-starter.

"If (Mulcair) believes he can open the Constitution without talking about Quebec's demands and those of the First Nations...it's completely unrealistic," Duceppe said.

Mulcair told the CBC on Wednesday that an NDP victory next month would give him a mandate to talk to the provinces about abolishing the upper chamber.

He also said he is confident that Senate-bound legislation would become law.

"The Senate is going to have to realize there's a government that's just been elected with, I would hope, a majority in the House of Commons," Mulcair said.

"And when that legislation is enacted, or at least adopted, by the people who have been put there by Canadian voters, they (senators) are going to be given the legislation and asked to pass it so it can be promulgated into law."

Duceppe said the Bloc also want to scrap the institution but said the best way to do that would be through Quebec independence.

The Bloc leader made the comments at a news conference where the transport of petroleum products by train was the main topic.

He used the occasion to accuse the three main federal parties of giving priority to economic issues instead of public safety.

"For us, the profits of petroleum companies are less important than the safety of Quebecers," Duceppe said.