U.S. Secretary of the Navy Ray Mabus is set to visit New Zealand this week for a trip that could move Washington closer to resolving a decades-old dispute with Wellington over port calls for U.S. vessels, it was learned Monday.

During his trip, Mabus plans to discuss a range of issues with military officials, including the first formal invitation for a U.S. naval vessel to visit since the country passed nuclear-free legislation in 1987, a statement posted Monday to the website of the U.S. Embassy in New Zealand said.

The Royal New Zealand Navy is celebrating its 75th anniversary later this year and has extended a formal invitation to the U.S. The statement, however, stressed that the anniversary invitation is not the purpose of Mabus' visit.