Greater Sydney's population is predicted to expand by an additional 1.7 million residents by 2036, and greater western Sydney is tipped to absorb two-thirds of this growth.
Australian Community Media looked at population projections in the following Local Government Areas (LGA): Bayside, Blacktown, Camden, Campbelltown, Fairfield, Georges River, Hawkesbury, Liverpool, Penrith, Sutherland and Wollondilly.
This is what we found.
Airport spearheading growth
The largest rise is to be in the Camden LGA, where the population is expected to grow 85.07 per cent, from 127,650 in 2021 to 236,250 by 2036, according to data from NSW Department of Planning, Industry and Environment (DPIE).
The second-largest rise is to be in the Penrith LGA, where the number of people is projected to grow 52.3 per cent from 230,300 in 2021 to 350,900 in 15 years.
In the heart of the south-west, the rapidly-expanding multicultural hub of Liverpool is expected to grow 51.25 per cent, from 251,300 people to 380,100.
The Western Sydney Airport and Aerotropolis are set to open in the Liverpool suburb of Badgery's Creek in five years, contributing to 200,000 new jobs expected in the Western Parkland City.
The DPIE says the area is set to become "a high-skill jobs hub across aerospace and defence, manufacturing, healthcare, freight and logistics, agribusiness, education and research industries".
Liverpool City Council Mayor, Wendy Waller, said approximately 30 new families are moving into the Liverpool LGA every week, translating into an increasing need for more schools, health care, child care, aged care and improved connectivity to the region's transport network, which is "at capacity in many areas".
She said there is an "urgent need" for Fifteenth Avenue to be upgraded to support the council's project, the Fifteenth Avenue Smart Transit (FAST) Corridor, designed to support growth and deliver public transport between the Liverpool CBD and the new airport and surrounds.
"The FAST Corridor will help reduce sprawl, improve public transport, and preserve the unique character of our region," Ms Waller said.
"We are calling on the State and Federal Government to come to the table with additional support, funding and better infrastructure planning to ensure Liverpool City can sustainably manage further population increases and the associated demand for more facilities."
Also with high projected population increases are Blacktown with 38.3 per cent (growing from 411,650 to 569,500), Wollondilly with 35.73 per cent (growing from 54,150 - 73,500), and Campbelltown with 26.6 per cent (from 180,050 to 227,950).
The LGA of Fairfield, bound partly by the fast-growing LGAs of Blacktown, Liverpool and Penrith, is expected to grow at a meagre rate compared to its neighbours, rising 21.33 per cent from 210,000 in 2021 to 254,800 in 2036.
Restrictions hampering development
In the semi-rural Hawkesbury LGA in Sydney's north-west, which neighbours Blacktown and Penrith, the population is expected to increase only 14.74 per cent over the next 15 years, from 67,150 to 77,050.
According to Hawkesbury City Council's Local Housing Strategy, housing growth must be balanced with the area's "high-value natural environment and strong cultural heritage".
Hampering development in a significant portion of the LGA is the risk of flooding along the Hawkesbury River, where communities from Wisemans Ferry to Yarramundi are based.
Other significant physical environmental constraints include the area's colonial heritage buildings, bushfire risk, proximity to UNESCO World Heritage-listed areas, rural identity of the villages and the need to protect productive agricultural land.
Hawkesbury City Council Manager Strategic Planning, Andrew Kearns, said the expected population increase required the "timely delivery of adequate infrastructure such as additional open space embellishments, community facilities, public transportation, improved road network, health and educational facilities".
Slower growth from within
On the opposite side of the city, in the Sutherland Shire, the population rise is also expected to be more meagre than much of the rest of greater Sydney, from 239,200 in 2021 to 258,800 by 2036 - a growth of 8.19 per cent.
Despite the locale's transport links to the City of Sydney and its proximity to the Western Sydney Airport, much of Sutherland's population rise is expected to be generated locally, as families continue to grow and subsequent generations remain within the LGA.
The area is known for its bays, beaches and bushland. Sutherland Shire Council will align future planning changes with the capacity of existing and planned infrastructure, and advocate for improvements to the area's public transport and road networks.
A spokesperson for the council said local government had a vital role to play in facilitating the right mix of housing options that would "meet the future needs and aspirations of local residents, and to deliver infrastructure and services that will continue to support the high quality of life we all enjoy for future generations to experience".
Nearby Bayside's population expansion is also on the lower side, expected to rise 14.9 per cent from 198,950 currently to 228,70 by 2036. Another neighbouring LGA, Georges River, is on the lower end of the scale, with a 13.31 per cent increase expected over the next 15 years, from 161,500 to 183,000 people.