Labor has used the Transport Minister's idea of constructing tunnels under Perth's main roads to ease congestion to paint the Government's transport planning as chaotic.

Transport Minister Dean Nalder believes tunnels constructed beneath existing roads would be part of a long-term solution to manage congestion.

But the Opposition has attacked the Minister in Parliament, accusing the Government of failing to have a clear plan for meeting Perth's transport needs.

"Transport is one of the most important things confronting our city and our state," Opposition Leader Mark McGowan said.

"Transport is a long-term issue for our state.

"There is no integrated or coordinated plan from the Government whatsoever."

WA transport planning 'mayhem'

Mr McGowan described how major transport initiatives like Max Light Rail had been delayed and fundamentally changed, from light rail, to rapid transit buses, and possibly to heavy rail.

He cited the trouble-plagued Perth Freight Link, which had been scaled back from reaching the Fremantle Port, only to be shelved for at least 12 months after the Supreme Court found environmental approvals were invalid.

"I've just given a small snapshot over the past two years of the twisting and turning, of the pandemonium, in transport planning in Western Australia," he said.

"And today's story [on tunnelling] is just another example of that mayhem that is going on in transport planning in Western Australia."

Mr Nalder countered the barrage of Opposition criticism, arguing proof of the Government's plan was in projects already being built, on time and ahead of budget.

"Those opposite would have you believe that we don't have a plan, but I can tell you that when you actually look at what is being delivered, you can actually see these things coming together," he said.

Mr Nalder said even huge projects like the billion-dollar Gateway interchange near Perth Airport had been completed ahead of time and under budget.

He contrasted that with the Opposition's MetroNet plan for building more rail lines, more train stations, and fixing level crossings across the city.

Without costings and deadlines, Mr Nalder does not believe Labor could afford it.

"How? How are they actually going to do it?" he said.

"I believe that the transport plan they have opposite is just not credible at all."