NDP incumbent Ryan Cleary and Liberal challenger Seamus O'Regan went head-to-head at CBC's studios on Tuesday night for a live radio debate on who should represent St. John's South-Mount Pearl.

Radio debate: Ryan Cleary, Seamus O'Regan 1:00:15

While the candidates argued about several policy issues, the debate also got personal — even after Cleary promised it wouldn't.

"I'm not going to question your patriotism," said Cleary, when asked about the fact that O'Regan had lived outside of Newfoundland and Labrador for 15 years. During much of that time, O'Regan hosted CTV's Canada AM.

"I think you're a good Newfoundlander and so am I," Cleary said. "I made a commitment not to take shots, and I'm not going to do that this evening."

However, 30 minutes later, the discussion got heated. During debate on small business tax credits, Cleary took a shot at O'Regan's commitment to Newfoundland and Labrador.

"Are you representing Ottawa in Newfoundland and Labrador, or Newfoundland and Labrador in Ottawa?" Cleary said.

"What are your priorities, Seamus? Jeez b'y, you spent too many years on the mainland…. Sorry, but with that one, you had it coming."

A half-hour after promising not to make personal attacks, Cleary suggested that O'Regan had spent "too much time on the mainland." (CBC)

After the debate, Cleary told reporters he was not sure if O'Regan was connected to Newfoundland and Labrador issues.

What are your priorities, Seamus? Jeez b'y, you spent too many years on the mainland. - Ryan Cleary to Seamus O'Regan

"I think that if you want to know Newfoundland and Labrador inside out, you've got to live it and breathe it," Cleary said.

"I have done all of my work here, and I think my strength is the fact that I feel my finger on the pulse. I feel connected to Newfoundland and Labrador. I don't know if that's necessarily his strength."

O'Regan, who started his career in St. John's as a provincial Liberal aide, came back to Newfoundland and Labrador in 2014 to prepare a run for federal politics.

$15 minimum wage is 'malarkey,' says O'Regan

The candidates also sparred on policy issues. O'Regan persistently criticized the New Democrats' plan to balance the budget, while calling the party's policies unrealistic.

"I have to take issue with the NDP as a party," he said when Cleary brought up the NDP's plan for a national childcare strategy.

"The bottom line is that every single promise that they make — including child care — has an asterisks after it that says, 'Only if we balance the budget based on Stephen Harper's numbers.'"

Throughout the rest of the night, O'Regan frequently interjected Cleary's policy statements with the word "asterisks," saying the NDP's policies would only work under an unrealistic balanced budget.

While Cleary said increasing the federal minimum wage to $15 an hour would help get more workers for local businesses, O'Regan called the idea foolish.

"A $15 national minimum wage is malarkey, it's nonsense. It's false," said O'Regan, arguing that a $15 wage would hurt local businesses, it would disturb the economy, and it wouldn't work with the provinces.

Seamus O'Regan frequently criticized the NDP's plan to balance the budget and called the party's policies unrealistic. (CBC)

A question on helping people with autism stumped both the candidates.

Cleary began discussing the NDP's failed attempt to implement a national dementia strategy, but when steered back to the original question, he could not generate a specific answer.

O'Regan said he also could not provide specifics, but that he appreciated Cleary's honesty.

"I respect Ryan's answer, because to be honest with you, the last time I said to anyone in the media that I was going to go off and research something before I came back with specific answer, I seem to have gotten into a whole lot of trouble," he said.

O'Regan took hefty criticism in June when he walked off-camera during an interview with NTV News, leaving the impression that he wasn't prepared to answer questions about labour relations in the country.

Cleary also frequently steered the debate towards scrapping the shrimp fishery's controversial "last in-first out" policy, which NDP Leader Tom Mulcair recently announced he would "fix."

Both Conservative candidate Marek Kroll and Green Party candidate Jackson McLean were invited to participate in the debate, but declined the invitation.

CBC will host another radio debate for the candidates running in the riding of Avalon on Thursday at 8:30 p.m. NT.

Live blog

Follow updates from Tuesday night's St. John's South-Mount Pearl debate in our live blog.