Phase 1 of the project comprises a 22km Y-shaped line running from the Balga college campus in the north via the city centre to separate termini at the Queen Elizabeth II Hospital and Victoria Park.

The line will run along Alexander Drive, one of Perth's busiest public transport corridors, serving education, retail, and leisure centres.

The total project cost is likely to exceed $A 1bn, with funding expected to come from a combination of state, federal and private sector sources.

Commercial services are expected to start in late-2018, and the state government anticipates daily ridership would reach around 35,000 by 2031.