The Herald has mapped federal government data showing where new homes have been approved for construction in Sydney over the past two years. Not all will be built, but the figures indicate where the development is focused and how it will change the face of the city.

"The data highlights the schizophrenic nature of Sydney's housing supply," says Bill Randolph, the director of the City Futures program. "It's either low density [on the] fringe or high density in the central city."

But, on balance, Sydney, is becoming denser, and quickly.

Apartments make up little less than 70 per cent of these newly approved homes and the next three years will bring an all-time record of apartment construction.

In 2011, only about one-quarter of Sydney's residents lived in apartments.

The figures also show that Sydney is skewing north. The state government has two big priorities for new development on the city's north-western and south-western fringes.

The north-west is peeling ahead. Apart from a boom in Sydney's centre, developers are targeting Parramatta, Blacktown, the Hills and, increasingly, Auburn and Ryde, for a wave of new residents drawn by better transport and proximity to professional jobs.

NSW Housing approvals are at their highest level since 2000, according to the Australian Bureau of Statistics, with more than 52,000 approvals made in the past 12 months.

Minister for Planning Pru Goward said: "We know there will be 2 million extra people living in NSW by 2031, which means we will need about a million more homes."

But with growth comes stress. Recent reports show that Sydney's growing and sprawling population is becoming the biggest problem for government service delivery.

Here, we survey the challenges Sydney faces in catering for new residents in three key fields.

Transport

The trouble of travelling from western Sydney to the CBD has been Sydney's most obvious transport issue for decades. That is likely to be compounded by surging growth in Parramatta and Blacktown.

"Parramatta and Blacktown are heavily reliant on the western Sydney rail line – the most overcrowded line during peak hours," said Michelle Zeibots from the Institute for Sustainable Futures at the University of Technology, Sydney.

The western line runs at 120 per cent of its capacity most mornings.

Most of western Sydney's roads are similarly overloaded: ranked on a six-letter scale of capacity with "F" as completely dysfunctional, they come in at an "E" or "D".

"If the west is lucky, those in government [will] secure new public transport initiatives like the Parramatta light rail," Dr Zeibots said. "[New] motorways like WestConnex will not help the west or support greater development because any new traffic on the motorway network eventually has to come off onto [already congested] local roads."

Overcrowding is starting to affect the fast-growing development of Green Square, just south of the city's centre. Of the 117 buses that pass through the area around the Green Square development every morning, many are full on arrival and car traffic is expected to increase by one-third in coming decades.

Newly approved projects such as Meriton's 1000-tower Mascot Central project will only compound these problems.

Transport consultant Alex Gooding notes that while transport planners are welcoming new rail links to support the north and south-west, less attention is being paid to the new growth suburbs that fall outside their reach.

The south-west rail link will reach suburbs such as Leppington before development takes off, but there is no planned connection for two of Camden's newest and fastest-growing suburbs in Oran Park and Turner Road.

Only about 7 per cent of people in Camden – the seventh-fastest growing area – use public transport.

And in the north-west, though planners are hailing a new rail link, it has not yet been connected to one of the Sydney's newest areas of future development: Marsden Park, the future site of 30,000 homes.

Jobs

A lack of transport connections and what in urban planning lingo is called "connectivity" are linked closely to the other major problem of Sydney's development: jobs.

The government's strategy is to move both people and jobs into its growth new areas in the north and south-west.

There are nearly 400,000 workers in the north and south-west, according to a report by consultancies Essential Economics and Geografia. But only about 250,000 of them have jobs within the region.

In a little more than a decade, 200,000 new workers will pile in, putting further stress on transport networks if local jobs are not created.

Professor Randolph says the economy in the north-west is shaping up better. The economy there is being helped by transport connections to professional jobs in the Hills and Parramatta, which is in turn propelling the area's housing market.

"But [Sydney's] south-west is still economically adrift," he said.

The state government, however, is touting a "renaissance" in the development of land by employers in the area between Liverpool and Camden.

Statistics seemingly back up that claim. The amount of land being used by employers in the area is now up by one-third since the government took office and land purchases have hit $600 million this year.

But Phil O'Neill, a geographer from the University of Western Sydney, doubts the logical leap that land being bought by employers is leading to the government's claimed "blue-collar jobs boom".

Most of this "employment land", he notes, is being taken up by large transport and logistics warehouses lining motorways.

On average, Professor O'Neill says, a warehouse or logistics company employs about 20 people for every hectare of land it uses, much less productive use of land than the disappearing manufacturing industry.

This compares unfavourably to the kind of high-density employment in inner-city offices and tourism, most vividly demonstrated by the Barangaroo urban renewal project which will provide about 50 times as many jobs.

A second airport at Badgerys Creek is the south-west's great new hope.

Education

The Education Department is anticipating a massive shortfall in school funding over the coming two decades.

On its own projections, the department will fall about $7 billion short of the money needed to fund 230 new schools for a rise in Sydney's student population of one-third.

"It caught us by surprise," a senior department source said of a projected rise in medium and high-density housing in the north-west.

Internal documents reveal the department is particularly concerned about housing students for new suburbs created on the south and north-western fringes.

Sydney's two fastest growing schools, Elderslie in Camden and John Palmer Public outside Blacktown, have both recorded a doubling in enrolments in the past three years. 

But the government's biggest concern over the next two decades is the expected massive increase in the area around Parramatta and Ryde.

Meanwhile, the government is yet to close a deal on a new site for an inner-city high school where not only a rising population, but a growing and unexpected preference for public education among parents is seeing student numbers rise.

The City of Sydney's demographic forecasts predict the school-aged population will grow by more than 7000 between 2006 and 2021; nearly three-quarters of those children attend public schools.