A Liberal MP ramped up a testy running debate with former Conservative leadership candidate Maxime Bernier Monday, dismissing Bernier's latest tweets on the subject of systemic racism in Canada as "nonsense."

The dispute, which kicked off in early March, bubbled up again this past weekend when Liberal MP Celina Caesar-Chavannes gave an interview to the Globe and Mail. In it, Caesar-Chavannes criticized Bernier for not recognizing his "privilege" or recognizing the challenges faced by people of colour.

"You sit there and say you don't see it. Well, good for you, because you've never had to experience it, sweetheart," the newspaper quoted her as saying.

Bernier hit back on Twitter, saying Caesar-Chavannes was too focused on personal matters and not enough on policy.

"That's the main difference between us. You think the world revolves around your skin colour. My goal is to bring better policies to all Canadians. That's an MP's job," Bernier said. "And by the way, I'm not your 'sweetheart.'"

On Monday, Caesar-Chavannes reacted to the tweet and her own comments in the Globe, saying "there is a bigger issue there than 'sweetheart'."

"I think it's nonsense," Caesar-Chavannes said of Bernier's tweet. "I don't think everything revolves around my skin colour. I think that there are race issues that we need to deal with and, again, for someone like Mr. Bernier to not see that is foolishness.

"I think him saying that I focus on my skin colour, and making things personal, is ridiculous."

"He votes on laws that impact millions of people and some of those millions of people face significant barriers in our society that need to be addressed, and our government addresses them and he diminishes them."

Bernier's office has yet to reply to requests for comment.

Liberal MP Celina Caesar-Chavannes responds to tweets from Conservative MP Maxime Bernier that say she thinks 'the world revolves around' her skin colour. 1:27

Conservative MP Erin O'Toole said that difficult debates about topics such as systemic racism in Canada should be held in Parliament and not on Twitter.

"I think certainly if any MP, whether it's Celina or anyone else, has concerns about racism, or stereotypes, or a whole range of things, this is the place to debate it," O'Toole said. "People should be willing to debate on both sides of things and if they have disagreements, don't do it just on Twitter, do it in the House of Commons."

This isn't the first time Bernier and Caesar-Chavannes have crossed swords over social media.

Immigration Minister Ahmed Hussen tweeted Feb. 28 that the federal budget was historic for "racialized Canadians."

Debating racism

The budget included money for a national anti-racism plan, mental health supports for at-risk black youth and funding to collect better data on race, gender and inclusion in Canada.

On March 2, Bernier responded to say "racialized" was "awful jargon" and accused the Liberals of using it to create division.

"I thought the ultimate goal of fighting discrimination was to create a colour-blind society where everyone is treated the same," Bernier said on Twitter.

Hussen responded that the budget was about equality and growth for all Canadians and that the idea of not seeing colour may sound great in theory but wouldn't address the realities of racism.

"At best, it allows the (Conservative Party) to continue to wipe their hands of playing an active role in the work that must be done to eradicate racism (and) at worst it means you are supporting the status quo by denying the very real experiences of people who live with racism every day," he wrote.

Caesar-Chavannes chimed in after that, telling Bernier "do some research, or a Google search, as to why stating colour blindness as a defence actually contributes to racism. Please check your privilege and be quiet."

She later apologized for the tone of her tweet and offered to meet Bernier to discuss the issue. Bernier refused the invitation.