Labour leaders past and present are pushing back against New Zealand's interest in joining AUKUS, describing Australia's military tie-up as an attempt to "wedge" China and a trade threat.
Three-term Labour prime minister and New Zealand's leading internationalist Helen Clark has teamed up with her 2005 election rival, then-National leader Don Brash, to voice their opposition to the pact.
Criticism has also come from the current Labour opposition and in the nuclear-concerned Pacific.
Flare-ups over foreign policy between major parties are rare in NZ, which considers itself to walk a middle road between the major powers in Washington and Beijing, with a proudly "independent foreign policy".
The right-leaning coalition government, formed late in 2023, has signalled interest in joining pillar two of AUKUS, the trilateral pact between Australia, the United Kingdom and United States, from which Australia will receive nuclear-powered submarines.
Pillar two centres on sharing advanced military technologies, including artificial intelligence, hypersonic and undersea technology.
AUKUS members have sounded out membership interest from allied countries such as Canada, NZ, and possibly Japan, though Australian Defence Minister Richard Marles has stated that would be in the "longer term".
NZ's confirmed interest came earlier this month at a joint foreign and defence ministers meeting in Melbourne, which resolved that Australia would send officials to Wellington for a high-level briefing.
To Ms Clark and Mr Brash, writing a joint opinion piece in the NZ Herald on Tuesday, that decision "appeared to abandon our independent foreign policy in favour of unqualified support for America's 'China containment policy'."
The pair assert NZ "instead decided to throw in our lot with America's attempt to slow China's economic rise and keep it tightly hemmed in by American forces" in the region, and petition Prime Minister Chris Luxon to reverse course.
"Prime Minister, it is imperative that you either reassert New Zealand's independent foreign policy by making it clear that we want no part of AUKUS, or of any other alliance designed to make an enemy of our largest trading partner," they write.
The Labour opposition has also cooled on the partnership since leaving government.
Foreign affairs spokesman David Parker said his party wanted to "stimulate a mature discussion" on the matter.
"The world is a more dangerous place than it was a decade ago. But that doesn't mean to say that we should position China as a foe," he told Radio NZ.
"They are a rising superpower, you would expect them to be a bit more active in the military space."
Mr Parker suggested plans to double defence spending from one to two per cent, or an extra $NZ4 billion ($A3.8 billion) annually, should also be questioned.
"Would we be better spending that on helping Pacific nations with infrastructure, helping them defend their economic zones, and fish their fisheries for their own benefit?" he asked.
"We're not yet convinced that AUKUS pillar two offers anything to New Zealand, that won't come to us for our existing mechanisms."
Former prime minister and current Labour leader Chris Hipkins said he "didn't see a huge amount of benefit" to pillar two membership, but was concerned about risks.
"We don't want to see AUKUS used as a wedge to basically create a sort of a US-UK-Australia divide with China," he said.
"I don't want to New Zealand to be part of a wedge".
Foreign Minister Winston Peters has also encountered opposition to Kiwi AUKUS involvement from Pacific nations he visited last week.
Leaders in Tonga and Samoa voiced concerns on largely anti-nuclear and pacifist grounds.
