The federal Liberal government has introduced legislation that will turn into law the informal ban on crude oil tanker traffic off B.C.'s North Coast.

Transportation Minister Marc Garneau tabled the legislation in Parliament on Friday, delivering on a promise made by Prime Minister Justin Trudeau in November.

The act introduced in parliament would prohibit oil tankers from carrying crude and persistent oils as cargo from stopping, loading or unloading at ports or marine installations in northern B.C.

The moratorium area would extend from B.C.'s northern border with the U.S down to the mainland adjacent to the northern tip of Vancouver Island, including Haida Gwaii.

Vessels carrying less than 12,500 metric tonnes of crude or persistent oil will be permitted in the moratorium area to deliver shipments to northern communities.

The legislation proposes that penalties for defying the moratorium reach up to $5 million.

"The Government of Canada is committed to demonstrating a clean environment and a strong economy can go hand-in-hand," Garneau wrote in a release.

"Tabling this legislation is another step towards fulfilling our promise to formalize the tanker moratorium on British Columbia's North Coast."

The proposed act is part of the Liberal government's $1.5 billion Oceans Protection Plan announced in November.