The policy change, part of efforts to bolster security ties, will "allow the US Secretary of Defense to authorise individual visits to Department of Defense or Coast Guard facilities in the United States and around the world," he said.
"I suspect that soon we'll be able to see one of those ships in our ports," he added, when asked when New Zealand vessels would stop in the US.
In a joint news conference with his New Zealand counterpart Jonathan Coleman, the Pentagon chief also announced that restrictions on meetings between defence officials and military exercises had also been rescinded.
"These changes I think are important and are in the interests of both our nations," he said.
The announcement underscored improving security ties between the two countries since a chill during the Cold War, when New Zealand imposed a ban on any visits by US nuclear-armed or nuclear-powered ships to its ports.
"While we acknowledge that our countries continue to have differences of opinion in some limited areas, today we have affirmed that we are embarking on a new course that will not let these differences stand in the way of greater engagement on security issues," Panetta added.
Coleman ruled out any change to New Zealand's policy on barring nuclear armed ships but said the two nations had "moved past" that issue.
The Australia, New Zealand , United States Security (ANZUS) treaty was suspended between Wellington and Washington in 1986, but in recent years both sides worked to enable close r militar y cooperation without restoring the provisions of the treaty.