Unionized crew members that work aboard Matson's trans-Pacific cargo ships authorized their union to call for a strike, a move that is intended to give the workers leverage in their contract negotiations with the company.

About 200 members of the the Sailors Union of the Pacific that work in Hawai'i voted overwhelmingly to authorize a strike.

The contract between Matson and the union expires at the end of June. Charles Khim, an attorney for the union, declined to discuss contract sticking points because of the sensitive nature of the negotiations.

The union is made up of unlicensed sailors that work in the deck, engine and steward's departments in U.S.-flag vessels. The SUP also has collective bargaining agreements with U.S.-flag companies where licensed personnel are represented.

The union has its headquarters in San Francisco with branch offices in Honolulu, Seattle and Wilmington, Calif. The SUP also maintains an office in Norfolk, Va.