Prime Minister Justin Trudeau has announced a $15.8-billion “full renewal” of Canada's Coast Guard fleet, with the addition of 18 new multi-purpose vessels to replace aging ships and two new Arctic patrol ships.

"The women and men of the Coast Guard have been making due with the vessels they have, some of which are almost as old as the Coast Guard itself," Trudeau said at a Wednesday morning news conference in Vancouver.

Some of the ships will be built at Seaspan Shipbuilding in Vancouver, where Offshore Fisheries Science Vessels are already being built for Coast Guard research missions.

"Dealing with this problem is long overdue," said Trudeau. "The previous government only promised 10 [vessels] and never funded them."

Trudeau hinted that a third shipyard will soon be selected to join the effort, as Seaspan and Halifax-based Irving Shipbuilding won’t be able to support the entire fleet renewal.

The new ships will deliver missions including light icebreaking and offshore patrol and search and rescue.

The Fleet Renewal Plan is updated every five years, but this is the first complete replacement the Coast Guard has had in over 10 years.

The announcement comes a month after the federal government announced a new $3.4-million Coast Guard Search and Rescue Station to be built in Victoria's James Bay neighbourhood.

Construction on the new base began in April and is expected to be completed later this year or in early 2020.