Panetta also said the United States was removing restrictions that would make conducting military exercises and security discussions between the two countries easier, Voice of America reported.
In 1985, New Zealand banned nuclear weapons, which prevented U.S. nuclear-powered and nuclear-armed warships from entering its waters. Soon after, the United States suspended its defense treaty with New Zealand.
Under the new policy, the U.S. defense secretary may authorize visits by New Zealand vessels to any Defense Department or U.S. Coast Guard facility in the world, VOA said.
New Zealand Defense Minister Jonathan Coleman said New Zealand's nuclear weapons ban will remain in place.
During a news conference Friday, Panetta said "differences of opinion" still exist in "limited areas" but the countries decided not to let those differences "stand in the way of greater engagement."
"I've long understood and appreciated the close bonds that exist between the United States and New Zealand," said Panetta, the first defense secretary to visit New Zealand in 30 years. "These are bonds of shared history, bonds of shared values and bonds of shared interests as two Pacific nations."
Panetta is finishing up a weeklong tour of the region.