The clock is ticking for the Canadian military to decide whether to replace its submarines, as Canada’s closest allies push ahead with plans to build new fleets.

The Royal Canadian Navy launched a push to replace the country’s four Victoria-class submarines nearly two years ago by creating a special team to figure out what Canada needs in a new fleet.

The move came in response to growing concerns about the age of Canada’s existing submarines and the amount of time needed to design and build such vessels.

But the federal Liberal government has yet to formally commit to buying a new fleet, despite submarines being at the heart of a new military pact between the United States, Britain and Australia.

Military commanders and experts say submarines are critical to defending Canada, including in the Arctic, as Russia and China build up their own underwater fleets.

But questions remain about whether this or a future government will spend the money needed to replace the current fleet, whose costs and benefits have been hotly debated since Canada purchased it from Britain in 1998.