China has raised its concerns about New Zealand being potentially involved in the intelligence and security pact AUKUS directly with the prime minister.
The issue was put on the table when President Xi Jinping and Christopher Luxon met in Peru on Saturday (local time) in what was their first face-to-face bilateral meeting on the sidelines of the APEC Summit in Lima.
The AUKUS defence technology partnership will deliver nuclear-powered submarines to Australia next decade - New Zealand has already ruled out joining that part of the arrangement.
However, the grouping of Australia, the US and the UK is looking to expand to new partners for what it calls 'Pillar Two'.
Rather than nuclear submarines, it would instead be focused on cutting-edge defence technology - covering areas like artificial intelligence, hypersonic missiles and cyber warfare.
Speaking to reporters following the leaders' retreat in Lima, the prime minister said New Zealand continued to investigate whether it might join Pillar Two, an alliance he described as a "positive" for the Asia-Pacific region.
Luxon said on Sunday that was not how China viewed it.
"We would disagree - we think it does give regional security and stability," he said. "They have concerns around what they see as tension in the region that's coming through the US, or what's coming through AUKUS."
Luxon said it was raised in the "same way we raise issues consistently with them about what's happening in the South China Sea".
As for what stage talks about joining Pillar Two were at, he said it was still with officials and going "very slowly".
Luxon said China raising the issue was no different to concerns Australia and New Zealand discussed around things like 501 deportees.
"If you've got trust in a relationship, you should be able to raise those differences."
Asked how China framed its opposition to AUKUS, Luxon said he did not want to get into the specifics.
On whether China would respond in some way if New Zealand joined AUKUS, he said: "That's just not a consideration for us. We're going to do this very objectively, very dispassionately."
Luxon said AUKUS in general terms "can be a positive to make sure there is stability and security in the region".
"In a region where we have huge amounts of tension and instability and potential instability, on balance we think AUKUS is probably a good thing in the region.
"Whether New Zealand gets involved or not is a conversation we continue to explore and get into."
Luxon has now wrapped up his short two days in Peru and returns to New Zealand on Monday.
Sign up for Ngā Pitopito Kōrero, a daily newsletter curated by our editors and delivered straight to your inbox every weekday.