After a 25-year ban, America will begin allowing Royal New Zealand Navy ships to visit US military and Coast Guard facilities around the world, Washington's Defence Secretary Leon Panetta said.
He added that the US is also removing restrictions to make it easier for the two militaries to engage in exercises and for leaders to hold security discussions as the US refocuses attention on the Asia-Pacific region.
"While we acknowledge that our countries continue to have differences of opinion in some limited areas, we have affirmed that we are embarking on a new course in our relationship that will not let those differences stand in the way of greater engagement on security issues," Mr Panetta said.
He spoke during a news conference on Friday at Government House in Auckland with New Zealand defence minister Jonathan Coleman.
New Zealand banned nuclear weapons from the country 25 years ago so US warships have not been able to enter its ports, and New Zealand ships were not allowed in US military or Coast Guard ports.
The New Zealand minister, however, said his country's ban on nuclear warships will continue. But he said the US has accepted that and the two countries have moved on.
Mr Panetta's visit to New Zealand, the first by a Pentagon chief in 30 years, is part of a US effort to rebuild military ties that were fractured over New Zealand's ban on nuclear warships.
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.
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 Mr Panetta said there were no plans to sign a new defence treaty with New Zealand at this point. Instead, they said leaders wanted to begin moving toward a new defence relationship that would allow greater defence cooperation, including counter-piracy measures, military exercises and training on amphibious ships.