Former Australian foreign minister and NSW premier Bob Carr intends to sue New Zealand Deputy Prime Minister Winston Peters for allegations made about Mr Carr's closeness to China, as a stoush over AUKUS turns feral.
The Labour opposition called on Prime Minister Chris Luxon to sack Mr Peters after the veteran called Mr Carr "nothing more than a Chinese puppet" and more on Radio NZ on Thursday morning.
New Zealand is mulling involvement in pillar two of the military tie-up, which will see AUKUS members - Australia, the UK and US - developing and sharing advanced warfaring technologies with other nations.
Mr Carr shared his criticisms of the US-led pact on a visit to Wellington in April, calling it "methane-wrapped bulls**t" and saying he admired Kiwi foreign policy as it wasn't as "gullible to the Americans" as Australia.
On Wednesday night, Mr Peters gave a major foreign policy speech at parliament, where he said New Zealand was yet to decide whether to collaborate as it had not been invited.
Followed up with a round of interviews on Thursday morning, Mr Peters launched an extraordinary broadside when he was asked about Mr Carr's criticism.
"What on earth does he think he's doing walking into our country and telling us what to do? We would no more do that in Australia than he should do here. That's the kind of arrogance we don't like," Mr Peters said.
Mr Peters called Mr Carr "nothing more than a Chinese puppet", before suggesting even further alignment in comments AAP has chosen not to republish.
Radio NZ has also edited an uploaded clip of the interview to remove the potentially defamatory remarks.
Mr Carr, currently in Europe, has issued a statement saying he intends to bring a defamation action.
Former NZ prime minister Helen Clark, who spoke alongside Ms Carr at the Labour-organised anti-AUKUS event in April, told Radio NZ Mr Peters had "seriously defamed" Mr Carr.
The spat roused Mr Hipkins to call for Mr Peters' sacking.
"Winston Peters has has embarrassed the country and created legal risk to the New Zealand government. The prime minister must do something about that," he said in Auckland.
Mr Luxon said while he wouldn't have said similarly, Mr Peters was "doing an exceptional job" as foreign minister.
"I'm sure Bob Carr as a seasoned politician understands the rough and tumble of politics," he said.
Even if he wanted to, Mr Luxon is unable to sack Mr Peters given his coalition government depends on the support of his NZ First party.
Mr Peters is not the first to question Mr Carr's links to Beijing.
Mr Carr led the Australia China Relations Institute at the University of Technology in Sydney after taking office.
Speaking to AAP in Wellington in April, he insisted he was not blind to China's misdeeds.
"Australia is entitled to challenge China, to press back against China's influence-building in the South Pacific," Mr Carr said.
"I've criticised China for militarising artificial structures in the South China Sea. I believe the extinction of legal autonomy for Hong Kong was wrong.
"I've always said Australia and other partners of China are entitled to press human rights and make specific reference to Tibet and Xinjiang province and the Uyghurs.
"No one's ever advocating that we not talk about deterrence, where it's required to maintain an honourable balance of power in Asia.
"But I've made very clear my reservations about AUKUS. $368 billion is the biggest transfer of wealth outside of Australia that has ever happened in our history."
Labour raised the issue in parliament on Thursday, where Mr Peters responded to criticism by holding up a copt of a 2018 Australian Financial Review article titled "How Bob Carr became China's pawn".