Australia's Defence Minister has had to defend the country's purchase of US nuclear-powered submarines.

Richard Marles told the ABC once their flag's flying on the three subs in the early 2030s, they'll be under complete control of the Australian government.

Australia will also be working with the US and UK to develop more submarines in future.

The announcement's sparked an angry reaction from China, which is accusing Australia of going down a "path of error and danger".

International relations expert, Professor Robert Patman says there are people here who are concerned New Zealand may be shut out of our region's defence discussions.

"New Zealand as a member of the Five Eyes, has very good bilateral relations with the US and Australia. It's also a partner of NATO, so I'm not sure that's the case."

LISTEN ABOVE