The strongest opposition to including issues such as gender equality in discussions over the North American Free Trade Agreement has come not from the United States but from within Canada, Prime Minister Justin Trudeau said Monday.

Speaking during a question and answer session at the first Toronto edition of the Women in the World conference, the prime minister said his government has faced hurdles in adding a gender chapter to NAFTA as it did in a free trade deal with Chile.

"The pushback we're getting is actually not from south of the border, the pushback we're getting is from Canadian Conservatives, who said 'Oh no this is about economics, it's about jobs... it's not about rhetorical flourishes of being good on environment or being good on gender,"' Trudeau said.

"To see that there is a supposedly responsible political party out there that still doesn't get that gender equality is a fundamental economic issue as well as many other things, that environmental responsibility is fundamentally an economic issue highlights that we do have a lot of work still to do in Canada."

Trudeau has positioned himself as a champion of gender equality since taking office, when he explained his decision to appoint a half-female cabinet with the headline-grabbing quip, "because it's 2015."

But he told the conference Monday that despite his government's efforts to bolster the ranks of women in politics, retention has proven a challenge, in large part due to the vitriol aimed at female politicians.

Trudeau said it is his goal to tackle the "hidden attitudes" that lead to inequity but stressed the matter won't be resolved during his tenure — rather, it will take generations.

PM Justin Trudeau tells an audience at the Women in the World Summit what he hopes to accomplish in the two years before the next federal election. 1:13

The Liberal government recently tabled a federal budget that promised to consider the way programs and policies impact different genders in different ways.

But the government is also facing criticism over the troubled national inquiry into missing and murdered Indigenous women and girls, with some families calling for a complete reboot of the process.

When asked about the controversy during Monday's talk, Trudeau admitted there were some difficulties but said the process was "on the right track."