HMNZS Te Kaha, a New Zealand frigate, in Canada. New Zealand does not have any nuclear warships but is now prepared to drop its policy of banning them from its waters

A 30-year ban on foreign naval ships that have nuclear capacity has been dropped by New Zealand in a move that promises to restore full military relations with Britain and America.

In 1985 the country’s Labour government under David Lange barred western warships from its ports if they had nuclear weapons aboard. The measure destroyed the so-called US defence umbrella but emboldened anti-nuclear campaigners.

John Key has invited the US to visit New Zealand DAVID ROWLAND/SNPA VIA AP

Now, timed to coincide with the New Zealand navy’s 75th anniversary celebrations in November, the government of John Key has invited the US navy to its shores.

Auckland said that it would not ask the US to confirm that an American naval vessel — the first that it has invited to visit in 31 years — is free of the nuclear