Chris Hipkins says New Zealand's strong nuclear-free stance was brought up in meetings with the United States and Papua New Guinea as the two countries signed a new security pact.
The Prime Minister was in Papua New Guinea on Monday for meetings with the country's leadership and other world leaders.
The gathering of leaders was a chance for some to sign deals, such as the US and Papua New Guinea, whose just-signed bilateral defence cooperation agreement will allow the two countries to "enhance security cooperation". It would also allow US aircraft, vehicles, and vessels to move freely within Papua New Guinea's waters.
Hipkins faced questions about whether this security pact could mean that nuclear submarines are allowed in the Pacific. While New Zealand is nuclear-free, he said it's important to recognise the autonomy of other countries.
"New Zealand's nuclear-free position is well-known around the Pacific and around the world and that's not going to change," Hipkins told reporters.
"What other countries do in terms of nuclear-powered warships or nuclear weapons really are questions for them."
He met with both sides of the security pact on Monday, Papua New Guinea Prime Minister James Marape and US Secretary of State Antony Blinken. Hipkins said New Zealand's nuclear-free stance was discussed in both meetings, including the fact that it wouldn't change.
But he remained tight-lipped on whether he knew what was in their security pact and what it allowed for.
In terms of his bilateral meeting with Blinken, Hipkins said the US acknowledged New Zealand's nuclear-free stance and that it wasn't going to change.
"They acknowledge that they want to have a security relationship with New Zealand as they have had in recent years and that we can continue to work together," Hipkins said.
"The nuclear-free stance doesn't need to be a barrier to New Zealand and the US continuing to have a good, strong relationship."
Earlier on Monday, Hipkins said he'd listened to Marape on what the deal would achieve for Papua New Guinea and it would be a "strengthened ongoing relationship" with the US.
"I would like to acknowledge this is not new territory for Papua New Guinea," Hipkins said.
"They have existing security arrangements with the United States. This is not just about security. It extends to a range of other things, including electrification and so on. I would see this more as an extension of an existing relationship."
Hipkins also said earlier that it shouldn't be assumed that all military partnerships are necessarily about conflict. Although there are concerns that it puts Papua New Guinea at the epicentre of a military storm between the US and China.
He said New Zealand doesn't support the militarisation of the Pacific, but also "military presence doesn't necessarily signify militarisation".