In a major speech on Wednesday night, Foreign Minister Winston Peters said Australia, the UK and US had not decided whether they wanted New Zealand involved.
"There is one crucial precondition and one consequential decision required before New Zealand could or would participate in pillar two," he said.
"AUKUS partners need to want us to participate in pillar two and invite us to do so.
"That precondition has not yet been met, which is why we are exploring with our traditional partners the scope of pillar two and seeking a much more detailed understanding of what this involves."
AUKUS is the military tie-up that will see Australia obtain nuclear-powered submarines from the UK and US.
A second pillar of the pact will see those powers developed and share advanced military capabilities, including cyber and AI-powered technologies, and hypersonic weaponry.
Last month Japan, and, on Wednesday, South Korea confirmed their interest in pillar two, with Canada and New Zealand mooted as possible members.
In a hint that Wellington stood ready to collaborate, Mr Peters spent long stretches of his 30-minute speech attacking critics of the pact.
Former prime minister Helen Clark and the current Labour opposition have argued against membership, saying it belies New Zealand's independent foreign policy.
"The critics are sadly out of date," Mr Peters said.
"There is ... an ideological element underpinning the critics' outright rejection of pillar two and their claim that we are abandoning an independent foreign policy.
"Their conception of our independent foreign policy has always carried a strand of anti-Americanism, so being independent means for them saying no to the United States.
"There is an old saying that nostalgia is the most seductive of liars. We think some of the critics are seduced by old battles, and projecting those onto the pillar two debate."
Mr Peters said it was prudent to explore the opportunities that pillar two provided, particularly as New Zealand rebuilds its defence capacity in the wake of attrition and growing security threats.
"if Australia adopts new advanced technologies what does that mean for New Zealand's ability to communicate with our ally's capabilities?Â
"It would be irresponsible for us not to consider whether (military assets) will still be fit for purpose under pillar two's technology advances."
Taking office in November last year, the 79-year-old is in his third stint as foreign minister, and has visited 14 countries since - including a week in the US last month.
He said one of the biggest messages from his travel abroad has been the importance of investing in defence in a deteriorating security environment - as evidenced by conflicts in Ukraine and Palestine.
"New Zealand needs to ask hard questions of itself. As we seek a more secure region and world, are we doing our share?" he said.
"New Zealand's long history of parsimony when it comes to defence cannot hold if we wish to continue garnering respect from, and influence on, others."
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