A frustrated Scott Morrison has been forced to publicly slap down Craig Kelly, after the Liberal backbencher got into a spectacular spat with Labor frontbencher Tanya Plibersek in Parliament House’s press gallery.

Wednesday morning’s corridor confrontation, in front of the cameras, and Kelly’s continued media blitz defending his advocacy of discredited or unproven alternative COVID treatments, were the last straw for Morrison, who feared Kelly’s behaviour could undermine the vital vaccine rollout due to start within weeks.

Plibersek had been attacking Kelly as a in comments to reporters, when he loomed up behind her.

In their subsequent heated exchange, she told him her mother lived in his electorate of Hughes and “and I don’t want her exposed to people who are not going to be vaccinated because of these crazy conspiracy theories that you’re spreading”.

Morrison had thought Kelly had agreed, when they spoke by phone on Tuesday, to avoid further provocative comments, which have centred in particular on his promotion of hydroxychloroquine and Ivermectin.

Kelly was immediately hauled in for what the Prime Minister’s Office described as a dressing down.

This led to his issuing a statement saying, “The Prime Minister reinforced the importance of public confidence in the government’s vaccine strategy.

"I agreed to support the government’s vaccine rollout which has been endorsed by the medical experts.

"I have always sought to support the success of our nation’s public health response during the pandemic.

"I believe the spread of misinformation can damage the success of our public health response during the pandemic.”

In Wednesday’s question time, the opposition’s attempt to pursue the Kelly issue was again frustrated by being ruled out of order. Morrison did not have a readymade opportunity to distance himself from Kelly, as he had decided he needed to do – after pointedly avoiding doing so earlier in the week.

Following question time Morrison made a statement to the House “on indulgence”, declaring he disagreed with Kelly.

“A key principle of our government’s successful response to the pandemic … has been respect for the expert advice, the expert medical advice … and the institutions, those who have the responsibility under our system for providing that advice.”

He said it was true that Kelly’s views “do not align with my views or the views of the advice that has been provided to me by the Chief Medical Officer”.

Morrison said he had made his view very clear to Kelly in their discussion.

“Vaccination is critical. It is our primary responsibility this year as we continue to respond to the pandemic.”

The Therapeutic Goods Administration was the authoritative body and it was respected around the world.

“So I can say to Australians – indeed, for the same reason that I and members of this place will take our own children, our own parents, to get that all-important vaccine – that our Therapeutic Goods Administration and the medical advice that guides my government’s policy on the pandemic … is the best in the world”