Bullsbrook is a blink-and-you'll-miss-it kind of place. The community of 6000, which lies 45km northeast of Perth, consists of a small parade of shops by the grand-sounding but not very huge Great Northern Highway and a few tidy tree-lined streets peering onto the bushland beyond.

This semirural suburb is a quiet place to live, bar the screech of the odd jet landing at RAAF Pearce next door.

But it's about to get a lot nosier. Bitumen is slowly replacing farmland, undergrowth is being cleared for new homes, and for sale signs are being hammered into patches of dirt.

Bullsbrook is at the forefront of a population explosion. Every year, 800 houses are expected to be built here. By 2051 as many as 85,000 people could call Bullsbrook home.

That's a 1300 per cent increase in residents and would make it almost twice the size of Bunbury, Western Australia's fourth largest city. It's just one of many suburbs stretched across the country that are about to see many, many more residents.

Bullsbrook has been a quiet semi rural suburb north of Perth. But things are changing. Picture: Wikimedia/Sean Mack

Local government areas (LGAs) in major cities are busy rezoning land to make the boom towns of tomorrow. And the boom is rarely as pronounced as in the outer suburbs.

City of Swan council, of which Bullsbrook is part and which expects its population to double to more than 300,000 in the next three decades, states it wants Bullsbrook to be a "liveable town that is sustainable, vibrant and prosperous".

But questions are being asked about how sustainable this swelling of suburbia is. Population watchers, who spoke to news.com.au, said the trend to keep expanding our cities outwards was "locking in tidal waves of congestion and deprivation".

The Bullsbrook masterplan envisages a whole new town being built 45km north of Perth.

BOOM SUBURBS TO GET EVEN MORE RESIDENTS

Every few years, state governments do some crystal ball gazing to estimate how many people will move into each LGA.

The most recent figures, released last year, forecast the population of many was set to shoot up far quicker then expected.

City of Swan is now expecting 40,000 more residents over the next decade than originally estimated just three years previously, The Australian reported.

Blacktown, in Sydney's west, already has 350,000 residents. By 2031 it could be a city of 526,000, at least 100,000 more people than live in Canberra.

Yet, in 2016, the NSW Government estimated Blacktown's population jump would be considerably lower to 480,000.

While some council areas and suburbs experiencing population booms are nearer CBDs - Melbourne and Sydney's Burwood, for instance - most are far further out. In Sydney that includes Liverpool, Penrith and the Hills; in Melbourne, Casey, Wyndham and Melton; and in Queensland, Ipswich, Moreton Bay and the Sunshine Coast.

Sydney’s new North West Metro terminates at Tallawong, currently little more than fields. It’s an example of infrastructure arriving before homes. Picture: AAP Image/Joel Carrett

LOCKING IN DISADVANTAGE

Professor John Stanley from the University of Sydney's Institute of Transport and Logistics Studies, told news.com.au that Melbourne had been growing at breakneck speed, piling on 25 per cent more people in 10 years, a figure almost unmatched globally.

"When you grow at that speed, the more affordable places are going to be on the fringe," he said.

That means long commutes of an hour - sometimes much more - to get to where the jobs are.

ABS data has shown that Melbourne's outer suburbs now accounted for 57.5 per cent of the city's population growth. However, in Melbourne's fringe there are just 389 jobs for 1000 residents compared to the city's core where there are 1229 per 1000 residents.

"There are very few services and jobs in these new suburbs so you lock in this tidal wave of congestion and disadvantage," he said.

A few kilometres to the west of Bullsbrook, Perth's new $1 billion NorthLink motorway is taking shape. City of Swan CEO Mike Foley told news.com.au the suburb was currently "well serviced by several major transport networks", That would improve with NorthLink as it could cut travel times by as much as 50 per cent, he added.

But while a railway line bisects the suburb, commuter trains terminate 30km south. And there are just a handful of buses a day to Bullsbrook

Stringing out new suburbs on the side of highways doesn't impress Prof Stanley.

"You can't just build more freeways. They may reduce congestion initially but they only encourage further sprawl which just sees the traffic build up.

"You need public transport. You need buses before houses. The problem with big infrastructure projects is what is forgotten is the small stuff like walking and cycling and making communities.

"We spend massive amounts on road and rail projects when there is a better return on the small stuff."

A new suburb that Prof Stanley said was doing it right was Springfield, southwest of Brisbane, which has shops, schools, offices, a hospital as well as CBD rail and road links.

Springfield, between Brisbane and Ipswich, has been held up as positive example of how to do new suburbs right. It has transport links, schools, hospitals, shops and offices.

Adam Leto, executive director of the Western Sydney Leadership Dialogue, a group bringing together public and private sector bodies in the city's west, said Sydney was on track for a population of 7 million in the next two decades.

"Greater Western Sydney is going to do the vast majority of the heavy lifting when it comes to growth," he told news.com.au.

Mr Leto said affordable land for big family homes, open green spaces and a history of welcoming immigrants were all behind western Sydney's expansion.

Camden in Sydney's southwest has similarities to the City of Swan. Both are semirural and are undergoing a housing boom.

Camden currently boats 100,000 residents. That number will almost double by 2031 and reach 300,000 by 2041.

Camden Council has moved its headquarters to Oran Park. This brand new suburb is projected to have 21,000 residents by 2026, more than five times the number that live in the historic town of Camden from which the LGA takes its name.

That's despite it being an hour by car from central Sydney.

However, in Sydney this is less of an issue than many other capitals as it has a history of significant economic centres away from the traditional CBD. The most obvious is Parramatta which boasts skyscrapers, one of Sydney's busiest transport hubs, shops, theatres and a university.

Oran Park is a rapidly growing suburb in Sydney’s southwest. Picture: Sam Ruttyn

SPEND MORE ON BOOM SUBURBS

Billions is being spent on western Sydney with the aim of a 30-minute commute from home to workplaces even for those living in these fringe boom suburbs.

"Sydney has a head start but there is work to be done," Mr Leto said.

"Now if you go out to southwest or northwest Sydney there still isn't the infrastructure to enable that lifestyle many people in other parts of Sydney take for granted."

He said there remained a tendency to build new suburbs first and then retrofit infrastructure later.

Certainly infrastructure spending in Australia has jumped - new trams and metros are popping up like fresh grass after the rain. But infrastructure experts have said spending is still playing catch-up after a decade of neglect.

Associate Professor Janet Stanley of the University of Melbourne Sustainable Society Institute said more radical action was needed to reduce the strain on Australia's new sprawling suburbs.

"It's greatly concerning that we have a federal immigration policy to bring in people but they're not taking full responsibility for their welfare."

As our cities expand outwards, the new suburbs are intruding on wildlife. Picture: AAP Image/Richard Walker

In many LGAs the population jump is split between natural growth from the existing residents and external migration.

"If you agree to take this number of people in, you have to provide enough resources for them so they can have a good life," she said.

Prof Stanley said density also needed to be increased. Spread out suburbs with single-storey homes means small populations that struggle to support the services that create a feeling of community.

Things were improving in Melbourne which has gone from 12 dwellings to 18 dwellings per hectare. But 25-30 dwellings should be the aim, she said.

Densifying inner suburbs, particular brownfield sites, was also essential, she said, as the closer you get to the CBD the more infrastructure is already in place.

"There's no lack of space in inner cities and if we improve densities we'd all be better off. If we don't we're never going to get our cities right."

Bullsbrook still has a rural air, the country is at the end of every street. But the bulldozers are coming, and with them hundreds of thousands of new residents.

benedict.brook@news.com.au

What were fields in Bullsbrook are now being redeveloped for housing. Picture: Google Maps