Russel Norman says he doesn't think children should be encouraged to go into boxing, saying it is about harming others.
Dr Norman had been speaking to The AM Show panel about recent controversy surrounding a motivational talk from Joseph Parker only open to Māori and Pasifika boys and their fathers.
But the topic quickly turned to the former Green Party leader's opinions around boxing.
"The purpose of boxing is to damage the other person's brain sufficiently that they lose consciousness and if you're engaged in this in a long term... it causes actual harm," he said.
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"I just have a problem with boxing, the aim of boxing, the actual aim is a knockout. Knockout means I damage your brain so badly by hitting you with my fist that you lose consciousness."
Dr Norman compared boxing to rugby, where injuries were only part of the whole equation.
"It's difficult to justify why you would allow it to continue given that the sole purpose is harm. People get hurt in rugby but it's not the purpose of the game, it happens but it's not the purpose."
Sports presenter Mark Richardson spoke up to say he believes boxing has a net positive gain due to gyms helping children off the street through their love of the sport.
Dr Norman said Richardson was entitled to his own opinion on the subject.
Newshub National Correspondent Patrick Gower came around to agreeing with Dr Norman though, saying he made a good point.
"Obviously Joseph Parker is an awesome guy and he is a role model," he said. "[But] where are the questions around it when he is promoting bashing?"
Newshub.