Speaking to about 350 members of the NDP's Quebec wing on Sunday in Quebec City, Mulcair said he supports legal measures to tighten security in the wake of last week's attack on Parliament Hill, but only if police are making full use of the powers that they have already.
"Before we say the solution to the problem is to give them more tools," said Mulcair, "make sure they know and are using the ones that they have."
For example, he said, the federal government should be working closely with provincial authorities to make sure the mental health acts across the country are understood and properly enforced by police.
Last week, the federal government indicated the government plans on strengthening Canada's security laws, including amending anti-terrorism legislation and increasing the power of CSIS.
Mulcair says new legislation won't be passed without thorough debate from the opposition.
"We’re going to ask the real tough questions, and we won’t be afraid. We’re not going to shy away from that debate," he said. "It’s going to be a tough debate, but we’re going to make it a respectful debate, and we’re going to try and bring those issues forward as solidly as we can."
In his speech, Mulcair also repeated his party's promise to introduce a Quebec-style national subsidized daycare program, and he reiterated the NDP's support for an inquiry into the deaths of murdered and missing Indigenous women.