It's an anniversary that looks set to pass without major fanfare, but for Greenpeace campaigner Steve Abel, what happened 30 years ago remains a defining moment in New Zealand history.

On June 8, 1987, the country became nuclear-free, after Parliament passed the New Zealand Nuclear Free Zone, Disarmament and Arms Control Act.

"It's a hugely important moment in our history - the moral stance we took against nuclear weapons," Mr Abel said.

"A lot of people would say it put us on the map. It's something to be very proud of and I think we should be taking a similar stance on more contemporary issues, such as climate change."

The anti-nuclear legislation was enacted amid a stand-off with the United States, which didn't send a naval ship to visit again until last November.

It also followed Prime Minister David Lange's forceful and witty appearance at an Oxford Union debate in March 1985, when he argued that nuclear weapons were indefensible.

"I remember as a 15-year-old how inspiring that was," Mr Abel said. "And of course there was the bombing of the Rainbow Warrior."

In July 1985, 12 years after New Zealand had sent a frigate into the Pacific to protest against French nuclear testing at Mururoa, French agents sank the Greenpeace flagship in Auckland, killing a crew member.

France eventually halted nuclear testing in 1996.

The anniversary of New Zealand's nuclear-free legislation comes a week before a United Nations conference to negotiate a ban on nuclear weapons resumes.

In Auckland, it will be marked on Sunday with a celebration at the Domain, where Mayor Phil Goff will unveil a plaque beside a pohutukawa tree.

There are also plans to form a human peace symbol, recreating what happened at the same venue in 1983.

(Source: NZN)