China has been invited to send a ship to New Zealand for the Navy's 75th anniversary later this year and it's "highly likely" one will come, Prime Minister John Key says.
The US has also been invited to send a ship but hasn't yet decided whether it will.
The anti-nuclear legislation affects any navy ship that comes to New Zealand, and in 1985 a visit by the USS Buchanan was blocked because the US wouldn't confirm or deny its nuclear capabilities.
A poll at the weekend showed three out of four of those questioned wanted a US Navy ship to visit.
Mr Key has to sign a waiver for any navy ship that comes here.
"Our anti-nuclear legislation isn't country specific, any ships that comes has to meet our law," he said at his post-cabinet press conference on Monday.
He said he made his decisions based on advice from MFAT.
"Whether they ask them or do it through open source intelligence I don't know, a lot of ships aren't nuclear-armed or nuclear-powered," he said.
"The Americans have for a long time had a neither-confirm-nor-deny policy but they've also had open source intelligence about whether ships are nuclear powered or nuclear armed."
China and the US both have nuclear armed submarines.