US Secretary of State Hillary Clinton signed an agreement on Thursday formalising a thaw in US-New Zealand relations after a row over nuclear weapons dating back a quarter of a century.

The deal signed by Clinton and New Zealand Foreign Minister Murray McCully calls on both sides to deepen cooperation in fighting climate change, the spread of atomic weapons and extremism.

It also commits Washington and Wellington to promoting renewable energy and boosting capacities to fight natural disasters.

"We have turned a very important page in the history of New Zealand-US relations," McCully said.

Clinton -- who was given a traditional welcome from tattooed Maori warriors when she arrived for talks at the parliament building -- hailed a relationship that she said is "at its strongest and most productive in 25 years."

In 1986 New Zealand banned nuclear-powered warships and those carrying atomic weapons from its waters, prompting the the United States to suspend the three-way ANZUS defence treaty -- which also involved Australia.

Washington put strict controls on military cooperation with Wellington as the relationship between the two soured badly.

But ties have warmed in the past few years as New Zealand contributed troops to the US-led mission to Afghanistan.

Prime Minister John Key, who was on hand for the signing ceremony, said this week that the declaration would not reinstate New Zealand as a full ally of the United States but would show "we've got the next best relationship".

The countries' military cooperation has increased in recent years and analysts believe Clinton's visit signals a willingness to work around controls imposed after the ANZUS suspension.

Clinton talked of opportunities for joint military exercises but deferred to US Defense Secretary Robert Gates for details.

"We want to cooperate across the board in every aspect of our civilian efforts and our military as well," she said.

New Zealand and the United States were strong allies during World War II and the State Department said in September that the relationship between the two democracies was "profoundly underperforming".

McCully said the agreement was "highly symbolic" and reflected the high ambitions both sides had for their links. Under it, the two countries would hold annual military talks and regular, high-level political dialogue, he said.

Clinton has already visited Guam, Vietnam, China, Cambodia, Malaysia and Papua New Guinea on her nine-stop tour, which will next take in Australia and American Samoa.

Clinton put her trip to New Zealand in the broader regional context.

"My visit is part of a committed concerted effort to restore America's rightful place as an engaged Pacific nation. In this, as in so many other endeavours, we have a strong partner in New Zealand," she said.

Clinton was originally scheduled to visit New Zealand in January but that trip was postponed following the 7.0-magnitude earthquake in Haiti, which killed around 170,000 people and left more than one million people homeless.

During her three-day trip to New Zealand, Clinton will visit the country's second-largest city, Christchurch, which was hit by a quake of similar intensity in early September.

While the tremor caused damage estimated at four billion dollars (3.15 billion US), it did not result in any loss of life, an outcome attributed to New Zealand's strict building standards in an earthquake-prone area.