It will become mandatory for all large ships sailing into the Northwest Passage and Canada's other Arctic waterways to report to the Canadian Coast Guard, Prime Minister Stephen Harper promised Wednesday.

Harper said he also wants to toughen environmental regulations in Arctic seas by expanding the range of the country's anti-pollution legislation.

The prime minister made the announcement Wednesday morning on his arrival in Tuktoyaktuk, N.W.T. as part of a three-day tour of the Northwest Territories and the Yukon.

Currently, large vessels — including cruise, mining and supply ships — voluntarily register with the Canadian Coast Guard's vessel traffic system in the Arctic, which helps keep track of the ships in case the coast guard has to respond to emergencies.

About 99 per cent of vessels that travel in Arctic waters enroll in the system known as NORDREG. But coast guard officials in the North told CBC News earlier this month that there is no way to be sure that everyone is registering.

A Senate report released in June called for a mandatory ship registration system in Arctic waters, a system that already exists on Canada's Atlantic and Pacific coasts.

Harper also announced that he wants to extend the scope of the Arctic Waters Pollution Prevention Act, doubling the legislation's range to 200 nautical miles from the nearest Canadian shore .

The prime minister arrived Tuesday evening in Inuvik, N.W.T., to kick off a tour that has followed several government announcements related to asserting Canada's presence in the Arctic — a topic that may surface should Harper call a federal election.