The United States has lifted a 25-year-old ban that prevented New Zealand naval ships from entering U.S. military ports, in a key step toward restoring military relations between the two nations.

U.S. Defense Secretary Leon Panetta said Friday during a visit to Auckland that Washington is also removing restrictions to make it easier to hold military exercises and security discussions.

Since New Zealand banned nuclear weapons from its territory in 1985, U.S. nuclear-powered and nuclear-armed warships have been unable to enter its waters. The U.S. suspended its defense treaty with New Zealand shortly thereafter.

At a joint news conference Friday with his New Zealand counterpart Jonathan Coleman, Panetta acknowledged “differences of opinion” still exist “in some limited areas.” But he said both sides have decided to not let those differences “stand in the way of greater engagement.”

Under the new policy, the U.S. secretary of defense may authorize individual visits by New Zealand vessels to Department of Defense or Coast Guard facilities around the world.

But Coleman said that New Zealand's nuclear weapons ban, which still enjoys widespread public support, will continue, saying the U.S. has accepted that fact and the two countries have decided to move on.

Military ties between Wellington and Washington have improved in recent years, with New Zealand sending troops to help fight U.S.-led wars in Afghanistan and Iraq.

Panetta, who is the first Pentagon chief to visit New Zealand in 30 years, is wrapping up a week-long tour of Asia, bolstering military ties as part of the Obama administration's strategic new focus on the region.

During his tour, Panetta has insisted that the so-called “pivot” is not aimed at containing China, though Washington has been critical of Beijing for its rapid military buildup and increased assertiveness in the Pacific.