AUCKLAND, New Zealand (AP) — US Defence Secretary Leon Panetta arrived in New Zealand on Thursday, becoming the first Pentagon chief to visit the South Pacific nation in 30 years as the US tries to rebuild military ties that were fractured when New Zealand banned nuclear warships from its shores.

In recent years the relationship between the two countries has begun to thaw, and in June officials signed a new defence agreement that focuses on building maritime security in the Asia-Pacific region, establishing regular policy dialogue and working together to counter threats.

New Zealand banned nuclear weapons from the country 25 years ago and as a result US warships may not enter its ports. New Zealand ships are not allowed in US military or Coast Guard ports or facilities.

Although the ban remains, the relationship between the two countries has improved significantly since New Zealand first sent troops to Afghanistan in 2003, and particularly since the centre-right National Party, which is seen as US-friendly, came to power in 2008.

Senior defence officials travelling with Panetta said there were no plans to sign a new defence treaty with New Zealand at this point. Instead, they said leaders want to begin moving toward a new defence relationship that will allow greater defence cooperation, including counter-piracy measures, military exercises and training on amphibious ships.

Advancing military ties with New Zealand is part of the US military's new focus on the Asia Pacific as the Pentagon shifts more troops and ships to the region. The US hopes to work with New Zealand in the South Pacific, where the Wellington government has close ties with other island nations.

Panetta has been on a week-long tour of the Pacific, with earlier stops in China and Japan. But throughout the trip he has insisted that the new pivot to the Pacific is not aimed at containing or threatening China. The US, however, has been critical of China's military buildup and wary as Beijing expands it economic reach and trade through the Pacific.

The officials, who outlined US goals for the visit, spoke on condition of anonymity because the meetings with New Zealand officials had not yet occurred.

Panetta also wants to thank New Zealand for its participation in the Afghanistan war. New Zealand has about 180 troops there, working as a provincial reconstruction team. So far 10 New Zealand troops have been killed, with five of those deaths occurring in August, including the first female combat casualty in the nation's history.

Panetta planned to meet with New Zealand Defence Minister Jonathan Coleman, Minister of Foreign Affairs Murray McCully and Prime Minister John Key.

The nuclear weapons ban is popular among the general public in New Zealand but remains a sticking point for the US in resuming a full military relationship. Officials said there is no consideration of sending only non-nuclear US ships to New Zealand.

Still, there have been tangible steps in recent months to forge greater defence cooperation.

During a visit in May, US Homeland Security Secretary Janet Napolitano signed agreements between the US and New Zealand to improve and increase intelligence-sharing on international criminal organisations, improve the flow of passengers and cargo between the two countries, and better identify threats to air safety.

And earlier this year, US Marines visited New Zealand for the first time in at least 25 years.