Perth light rail project delayed for underground line

Plans are being drawn up for an underground train line that would travel through Perth's northern suburbs.

The airport rail link will be Perth's first fully underground rail line, but it may also mean further delays for the much-anticipated MAX light rail project.

"Underground railway would have to be part of the future solution to the city. We haven't got anymore road corridor left," the Department of Transport's Director General, Reece Waldock, said.

"It's quite different the MAX, it goes on a different route but more importantly it extends far further to the north."

"There is no way you will be ever able to justify building both an underground and MAX," Opposition spokesman Ken Travers said.

Legislation for the MAX light rail was to be introduced this year, but that has now been delayed.

The opposition says that, along with the emergence of this proposed underground rail line, is a sign the project is not just delayed but dead.

MAX was originally due to be completed in 2018, but now the earliest finishing date is 2022.

"We've put it on hold for three years, look at the project and reassess it," Premier Colin Barnett said.

"But sending public transport to that north suburbs area is something this government will do."