The new US ambassador to New Zealand has acknowledged the country's nuclear-free stance and says he will not attempt to change it, despite personal preferences.

The ambassador told media he is not in New Zealand to change New Zealanders' minds on nuclear-free laws. He did express a personal wish to see nuclear-powered aircraft carriers able to visit New Zealand ports.

New Zealand's nuclear-free legislation currently prevents nuclear-powered vessels from entering the country's waters. The ambassador said New Zealand is playing its part on defence under current arrangements.