The Australian government is stepping in to build a second international airport in Sydney.
The $AU5 billion airport will be located at Badgerys Creek, 50km west of the city's centre.
Prime Minister Malcolm Turnbull said the government would take on the project after the operator of Sydney's existing airport turned it down, citing financial risks.
It comes more than 70 years after the idea was first conceived, and follows promises from successive governments.
The current Sydney Airport, 8km south of the city, has become increasingly stretched amid increased demand in recent years.
Decades of debate
Mr Turnbull described the airport as a "vitally important project" for both Sydney and the nation.
"The airport will be a major catalyst for jobs and economic growth in western Sydney, injecting more than $AU1.9bn into the economy during the construction phase alone," he said on Tuesday.
"It is expected to deliver 9000 new jobs to western Sydney by the early 2030s, and 60,000 in the long-term."
The Sydney Airport Group declined its first option to build the airport, citing "risks" to investors including demand and growth potential and construction costs.
The debate on the need for a second airport in Australia's largest city dates back to 1946.
"I think the community wants to see the project come to life as opposed to necessarily worrying about who builds or who operates it," New South Wales Premier Gladys Berejiklian said.
Details of the plan will be announced next week when Mr Turnbull's government unveils its annual budget.