The West Australian Government could save tens of millions of dollars by investing in infill developments rather than greenfield sites, according to research released by the state's peak property group.

Perth's metropolitan footprint has grown significantly in recent years and now stretches for more than 100 kilometres from Yanchep in the north to Mandurah in the south.

A study jointly prepared over the past year by the Property Council, Australian Greens party, Curtin University and urban design company CODA looked at the cost of developing infill lots compared to stand-alone greenfield sites.

Urban infill allows higher density developments, such as apartments and units, around key activity centres and train station precincts, while greenfield developments clear land for new housing estates on the fringes of the city.

It found the Government could save close to $95 million for every 1,000 infill lots developed compared to the greenfield sites.

The report said the cost to government to provide infrastructure including roads, water, communications, power, health, education and emergency services in greenfield sites was $150,390 compared to $55,830 in infill sites.

The Property Council said if the Government increased its infill target from 47 per cent to 60 per cent, the Government could save $23 billion by 2050.

Greens leader senator Richard Di Natale said the party put aside differences to get the groups to work together for a common goal.

"We are failing on some of the most basic metrics when it comes to how to design the places we live, work and interact with others in," he said.

"We continue to have development occurring on the fringes of our cities, we've got expensive infrastructure costs and we've learnt about some of those through the report and poor connection to services and almost a total dependence on the motor vehicle."

Poor planning has lead to reliance on cars

Senator Di Natale said Australian cities were some of the most car dependent in the world, which was a symptom of poor planning.

In Perth, he said, 90 per cent of all trips were made by car and people spent an average of 60 minutes commuting to work each day.

"The political priorities are directed towards building more roads, more extensions, more widening, tunnels and some of those mega roads projects you've heard about," Senator Di Natale said.

Jemma Green from the Curtin University Sustainability Policy Institute agreed.

"If we keep developing at this rate, the reality is we are going to be paying more tax and on top of that we'll also be creating a far less liveable city," Ms Green said.

Urban sprawl costs state $2.5 billion a year

"Business is also going to become a lot less efficient because congestion, as a result of sprawl, is costing the economy around $2.5 billion a year.

"In 2008 the state's debt was $3.8 billion and we could well be seen as the state that's won the lottery twice, we've had the iron ore boom and the natural gas boom and we have to ask ourselves, how did we get from $3.8 billion of debt in 2008 to 28 billion today to a forecasted debt of $40 billion in three years time?

"This report goes someway to explaining what's going on here, if we increase our infill targets from the current 47 per cent to around 60 per cent the savings to the taxpayer are around $25 billion."

CODA architecture and urban design director Kieran Wong said infrastructure must be removed from the political process.

"Things like establishing an independent state infrastructure body, we really do need to have a sense of de-politicising the delivery of infrastructure in Western Australia," Mr Wong said.

"There are excellent examples in the UK where infrastructure is removed from the political process."