US Deputy Secretary of State Wendy Sherman met Prime Minister Jacinda Ardern on Tuesday and described relations between the countries as "incredibly valuable," APA reports.
AUKUS was focused on nuclear-powered submarines and was taking all of the energy of the three partners because of the size of the project, Sherman told Morning Report.
"We've always said that going forward, as we look at other emerging technologies and what that may mean for everyone's security in the world, that there may be scope for others to join, so certainly if that time comes, New Zealand is a country with whom we would have a conversation."
New Zealand was improving its capability in the Pacific region with the P8 Poseidon aircraft.
The country had to make its own decisions about its defense budget and the capabilities it needed, Sherman said.
But, she said, it was a critical partner in the blue Pacific.
Is the US concerned by an increased presence and competition from China in the Pacific?
"I think the Pacific Island Forum has made clear that it's very critical that we are all cognisant of the security and the sovereignty of each of the Pacific islands," Sherman said.