Government leaders in the Yukon have joined a lobby to have the state of Alaska exempted from a proposed change in the interpretation of the Passenger Vessel Services Act they say will hurt their cruise-ship tourism industries.

Yukon and Alaskan officials are concerned with a U.S. federal proposal to change how the maritime act, created in 1886 as a way of ensuring a U.S. monopoly on passenger service between American ports, is interpreted.

The law prohibits foreign-owned vessels from transporting passengers from one U.S. port to another without stopping at a foreign port in between. Until now, most cruise lines have fulfilled the century-old requirement by making brief stops of a few hours only — at ports in Mexico or Canada, for example.

The new interpretation, introduced in November, would require all ships sailing under a foreign flag to spend at least two days docked at a foreign port.

"We have registered our concerns formally with the government of Canada, asking them to take up the issue with their respective counterparts [in the U.S.]," Yukon Tourism Minister Elaine Taylor told CBC News on Tuesday.

Hawaii had asked the U.S. government to strictly enforce the docking requirement, as that state's cruise-ship industry struggles with competition from foreign-based cruise lines.

The Hawaiian Islands are one of the few areas along the west coast where U.S.-flagged cruise ships operate. Most large cruise lines in west coast waters fly foreign flags.

Cruise company officials say if the new interpretation is accepted, Alaskan cruises that travel from Seattle would have to make 48-hour stops at ports in British Columbia, leaving them with little time to dock in Skagway, Juneau and elsewhere in southeastern Alaska en route to their final destination.

Town officials in Skagway say that could translate into 100 fewer cruise-ship sailings and 230,000 fewer tourists to the town this summer.

Skagway is connected to neighbouring Yukon by a highway, so Taylor said the effects of having fewer tourists would also be felt in the territory. The cruise industry accounted for 125,000 visitors to the Yukon last year, with most of them coming through Skagway.

"Five years ago, the number of visitors coming to the Yukon from cruise tours has actually increased by 121 per cent," she said.

Taylor said the Yukon is backing Alaska's request that the proposed interpretation apply to Hawaii's cruise industry but not Alaska's. The U.S. Department of Homeland Security, which is putting the proposal forward, has yet to respond to Alaska's protests.