Western Sydney faces major employment headaches and a jobs deficit of around 300,000 as its population balloons in the coming decades, according to a new report.

The population of Sydney's west is expected to grow to 9.9 million by 2036, and the National Growth Areas Alliance is concerned there will not be enough jobs.

According to their report, close to 500,000 who live in the area will need to travel to other suburbs to work every day.

NGAA executive officer Ruth Spielman said there needed to be more investment in infrastructure.

"What's important is to ensure there are jobs closer to home and we're fostering what's emerging as well as transport to get to jobs elsewhere," she said.

The NGAA's report included the suburbs of Auburn, Bankstown, Blacktown, Blue Mountains, Camden, Campbelltown, Fairfield, Hawkesbury, Holroyd, Liverpool, Parramatta, Penrith, The Hills and Wollondilly in their definition of western Sydney.

The Minister assisting the Prime Minister on Cities, Angus Taylor, said building the proposed Western Sydney Airport would help.

"Airports are the fastest growing job hubs in cities all around the world," he said.

However, the peak body representing western Sydney councils said the airport, which is due to be operational at Badgery's Creek by the mid 2020s, was not enough.

"If you look at the Badgerys Creek proposal, at the moment its just a series of press releases," said Western Sydney Regional Organisation of Councils president Stephen Bali.

The Federal Government said the airport was expected to create 9,000 jobs by the early 2030s and a further 60,000 jobs in the coming decade.

"You need a roads plan, you need a jobs plan, you need a health plan to connect Western Sydney which is going to make up 50 per cent of Sydney's population," Mr Bali said.

A combined Commonwealth, State and local government deal to address Western Sydney's ballooning population was due to be finalised by the middle of this year.

Despite missing that deadline, the Federal Government said it expected an agreement to be struck by the end of 2017.