The State Government will give homeowners and industry the power to bypass local councils in the biggest shake-up of WA planning laws in 50 years.

All single houses that comply with residential design codes will be exempt from approvals.

For developers, the opt-in threshold to go directly to assessment panels will be lowered and the mandatory threshold raised.

The WA Planning Commission will also become sole arbiter on structure plans guiding land use, subdivision and developments.

Other reforms to be announced today include online applications, a review of the WAPC and its infrastructure co-ordinating committee, a Statewide planning design policy and concurrent amendments to region and local planning schemes.

Taken with reforms started in 2009, including the introduction of assessment panels, the reforms are billed as the biggest since the metropolitan region scheme in 1963.

Planning Minister John Day said the reforms would make a substantial difference to the availability of land and the speed developments were approved.

"The changes will give people great confidence that the decision-making processes in relation to land and housing developments will be more timely and that there will be fewer unnecessary delays," he said.

"The buck stops with the State Government in relation to providing affordable and sufficient housing developments.

"Local governments don't get that criticism, generally, and so we want to work with councils where they're prepared to work effectively with us and the majority of local governments do that, so I think most people will understand the need for the changes."

WA's planning industry welcomed the plans but the WA Local Government Association was less enthusiastic.

President Troy Pickard was cautiously positive about some changes but warned making the WAPC the default decision-maker for structure plans risked depriving the local community of its voice.

"Local government would not be expected to support a process by which the local community is removed from having a substantial voice in new and neighbouring developments and the potential impacts on their amenities and facilities," he said.

Planning Institute of Australia WA president Charles Johnson said the reforms would concentrate planning on applications that required it and free councils to think more strategically.

He said many councils were all about development control with not enough strategic thinking. Processing applications dominated at the expense of strategies for things such as housing choice and affordability.

Urban Development Institute of Australia's WA chief executive Debra Goostrey said the group had lobbied for many of the reforms.

She said councils would not necessarily be sidelined because, although the opt-in value would be lowered, the mandatory value would be increased and those with faith in the council process could still choose that route.

But if the local government was bogged down in a range of ways, people would lean towards assessment panels.

"It's about creating market competition and understanding that time is money," Ms Goostrey said.