Perth's urban sprawl is now recognised as one of the biggest in the world.
And if the city continues to spread at the current rate, experts say the Perth metropolitan area will stretch 270km - from Myalup to Lancelin - by 2050.
Property consultant and City of Perth councillor James Limnios says urban sprawl is now Perth's biggest economic and social problem.
And Curtin University's sustainability professor Peter Newman says it is now time for Perth to embrace high-rise buildings.
In its latest audit of the populations and densities of almost 1000 cities, US website Demographia ranks Perth as the world's 59th biggest city in geographic size.
But of all the non-US cities in the top 60, Perth has the lowest population of 1.67 million people.
The ranking puts Perth just behind Manila (58th, population 22.71 million) and London (55th, 10.15 million) and ahead of Montreal (60th, 3.47 million), Tehran (71st, 13.42 million), Berlin (74th, 4 million) and Dubai (77th, 3.4 million).
"This report highlights the extent of urban sprawl in Perth which is costing families large amounts of money in transport costs and taxpayers who are funding infrastructure in the ever-growing newer suburbs of Perth," Cr Limnios said.
"We need to urgently implement a plan to encourage greater urban infill in near-city areas that will help reduce the geographic expansion of our city."
Cr Limnios said this urgent plan should include the development of big tracts of under-used inner-city land, such as land around McIver train station.
He said this area could be transformed into "an artistic precinct, similar to the Latin Quarter in Paris" that would appeal to young people and regenerate a blighted inner-city location.
Consideration should also be given to limiting first-homebuyers grants to homes within a 10km radius of the Perth CBD.
Professor Newman said the next 30 years of Perth's urban development could easily be accommodated within the existing sprawl, with more urban infill and high rise.
This would save money for the government and for families.
"Population growth is not a bad thing if it is used to generate more sustainable cities," Professor Newman said. "Every city needs to see its growth plan as an opportunity to create a better city - one that has a reduced footprint and a better livability.
"If low-density sprawl characterises the development, it will simply be a wasted opportunity.
"There has been high-density housing built in inner suburbs such as South Perth, Northbridge, East Perth and Subiaco.
"But places such as Fremantle, Cottesloe, Nedlands and Scarborough have actively prevented high density," he said.
City of Armadale chief executive and spokesman for chief executives from outer-suburban councils, Ray Tame, said policies to attract more people to live in inner-urban areas were expensive and took time.
In the meantime, he said new families were flocking "at the rate of a suburban street a week" to the new outer suburbs that promised a terrific quality of life.
"There is a clear push by industry sectors at State and national level to centralise knowledge, jobs and services in the central business district and then lay the question of traffic congestion and better public transport at the government's door," Mr Tame said.
"There has to be recognition this centralising must stop and jobs, services and the knowledge economy be decentralised … shortening the commute distance and providing affordable living."