Former foreign minister Bob Carr has unloaded on AUKUS and former PM Scott Morrison, describing parts of the alliance as “fragrant, methane-wrapped bulls–t”.

Carr, who was foreign minister from 2012-2013, told a foreign policy forum in the New Zealand capital that pillar two of AUKUS was a “science fiction” American invention designed to lure nations into a strategic alliance against China.

Carr said on Thursday the secondary pillar was “concocted” to “rope [others] in to an anti-Chinese alliance”.

“I don’t want to appall the diplomats present by using a vulgarism but it’s pure bulls–t …. pillar two is fragrant, methane-wrapped bulls–t,” he said.

“Why do I call it bulls–t? Because it has been cobbled together to make it look like there is more to AUKUS than subs. There isn’t.”

Carr, who is also a former NSW premier, argued it was folly for the US to pursue a foreign policy based on securing “primacy”, and said Australia was aligning itself too closely with the US in its power rivalry with China.

Under the primary AUKUS pact, Australia will receive nuclear-powered submarines from Britain and US in an attempt to shore up Australian security at a cost of hundreds of billions of dollars.

Under pillar two, AUKUS members would develop and share advanced military capabilities such as AI, quantum and hypersonic technologies.

The New Zealand government is actively considering membership of pillar two of the alliance, as are like-minded countries such as Japan, South Korea, and Canada.

In Wellington, Carr also criticised Morrison, AUKUS’s Australian architect, and his successor Anthony Albanese, for continuing support for the pact.

“Scott Morrison settled on AUKUS as a way of dividing the Labor party and seeing Labor isolated in the lead-up to an election,” he said.

“Labor – in what could be the biggest mistake by the Albanese government – didn’t say ‘we’re going to have a review, a review of the cost … and not a review of the opportunity cost’.”

Carr said the $386 billion cost to Australia could have delivered many more conventionally powered submarines, and represented “the biggest transfer overseas of Australian wealth in our history”.

Carr joined former prime ministers Helen Clark, of New Zealand, and Enele Sopoaga, of Tuvalu, at the forum in Wellington to argue AUKUS makes the Pacific less safe.

Clark, a proud champion of New Zealand’s independent foreign policy both during and after her prime ministership, agreed the question of alignment was central.

“We have to weigh up where we position ourselves as tensions have risen considerably between the US and China,” she said.

Clark argued for New Zealand to take a position of de-escalation of US-China tension, and de-militarisation in the Pacific.

“What is good about the ratcheting up of tensions in the region? Where is the military threat for New Zealand? What does AUKUS pillar two actually offer New Zealand?” she asked.

“Do we really need access to quantum technology for military purposes, an offensive cyber weapons capacity and hypersonic weapons?”

Thursday’s event was endorsed by the New Zealand Labour Party, with leader Chris Hipkins introducing Clark and saying the forum would influence his party’s policy.

Hipkins’ Labour government was also investigating membership of AUKUS pillar two but the party has abandoned its support since entering opposition last year.

NZ’s new coalition government, led by Chris Luxon and with Winston Peters as foreign minister, argues it has not decided whether to join up, and is merely continuing to explore membership.

-with AAP