OTTAWA -- Thwarting inappropriate behaviour amongst those who wield power and building on international trade agreements are both essential elements to creating a better country, Prime Minister Justin Trudeau said Sunday as he rallied his party's caucus a day before Parliament was set to resume sitting after its six-week winter break.

Trudeau told Liberal MPs that change is needed to encourage more women to enter politics.

"Add women, change politics is how we will make a better country," Trudeau told the gathering as he referenced a social media campaign the prime minister said was more than just a hashtag.

"Sexual harassment is a systemic problem. It is unacceptable."

His comments came as the recent movement against sexual misconduct, which saw the resignations since Wednesday of the Progressive Conservative leaders in Ontario and Nova Scotia, was felt within the federal Liberal caucus room.

Absent from the meeting was Trudeau's former sport and persons with disabilities minister, Kent Hehr, who resigned last week after being accused of sexual misconduct while he was a member of the Alberta legislature.

Liberal party whip Pablo Rodriguez confirmed Sunday that he had received another complaint about Hehr and passed it to the person in charge of the inquiry into the former minister's behaviour.

Meantime, Science Minister Kirsty Duncan was to formally take on Hehr's portfolio Monday at a Rideau Hall ceremony and retain it at least until the investigation is complete.

While Hehr remains a member of the Liberal caucus, the Prime Minister's Office said he decided not to attend the meeting.

Had he been there, however, Democratic Institutions Minister Karina Gould said she wouldn't have felt uncomfortable because of his presence.

"Sexual harassment on the Hill is a very serious issue, and we need to take it seriously," she said.

"But we also need to make sure that we're allowing due diligence."

Other Liberals, however, struggled over questions of why Hehr was allowed to remain in caucus while a fellow Alberta MP, Darshan Kang, resigned from the caucus last summer after being accused of sexually harassing two female employees in his office. Kang has denied the allegations and a PMO staffer said he resigned voluntarily.

Members of Parliament were expected to debate legislation Monday designed to strengthen sexual harassment protections for federal employees, including those working on Parliament Hill.

Labour Minister Patty Hajdu, who acknowledged there is a "whisper network" operating around the Hill, said part of the goal of Bill C-65 is to prevent misconduct. But she suggested it won't be easy.

"We're in an environment where we have high degrees of power, with parliamentarians, and often staffers who have very little power and are in often precarious work," she said outside caucus. "So it sets up an environment that is ripe for this kind of behaviour."

As Sunday's caucus meeting began, Trudeau also boasted about last week's signing of a new, comprehensive international trade agreement -- known as the CP-TPP -- that he said included significant gains for Canada over the former Trans-Pacific Partnership approved by the previous Conservative government.

The prime minister said his government hopes to make similar gains during negotiations on a new North American Free Trade Agreement with the United States and Mexico.

As the sixth round of talks to reach a deal were wrapping up in Montreal, Trudeau also set aside non-partisanship over NAFTA, accusing the Opposition Conservatives of being willing to bend to U.S. demands for changing the pact.

"They wanted us to sign the Trans-Pacific Partnership with no improvements," Trudeau said of the Tories.

"And if they had their way, we'd give into American demands on NAFTA."

While visiting Washington earlier this month, Conservative Leader Andrew Scheer said his party was united with the Liberals in seeking an updated NAFTA. Scheer has in the past, however, accused the Trudeau government of not properly spelling out a plan for the NAFTA talks.

The Conservatives said the resumption of Parliament will give Scheer an opportunity to once again pounce on the prime minister over his 2016 vacation with the Aga Khan.

Mary Dawson, whose tenure as federal ethics commissioner ended last month, found that Trudeau violated four provisions of the Conflict of Interest Act when he and members of his family stayed on the billionaire religious leader's Bahamian island.