Western Sydney will have its own international airport by 2026 even if the government has to step in and build it, the federal coalition insists.
Airport construction will begin by the end of 2018 at Badgerys Creek even if the Sydney Airport Corporation doesn't take on the project, federal Urban Infrastructure Minister Paul Fletcher said on Friday.
"Western Sydney airport is going ahead, regardless of who builds it," he told reporters in Sydney.
There is mounting speculation Sydney Airport, which owns and operates the city's existing airport at Mascot, will not meet the May 8 deadline to take on the Badgerys Creek project.
When Sydney's airport was sold in 2002 the new owners were given the option of developing and operating a second major airport in the city.
But the government has back-up plans if Sydney Airport decides not to take up that option, Mr Fletcher said on Friday.
"Our options are to build it ourselves, build it and operate it ourselves, or to identify another private sector party to build and operate the airport," the minister said.
But Mr Fletcher remains hopeful Sydney Airport Corporation will accept the project before the deadline and take on the responsibility of building and operating it.
"The ball is entirely in Sydney Airport group's court," Mr Fletcher told a Committee for Sydney event.
Blacktown mayor Stephen Bali says support for the airport was conditional on there being a curfew.
"There (must be) fairness and equity in relation to a curfew that we see at Mascot versus Badgerys Creek," Mr Bali said at Friday's event.
But Mr Fletcher said the government had made it clear Badgerys Creek would operate 24 hours a day, unlike Mascot where there's a ban on flights between 11pm and 6am.
Directing flights over less populous areas southwest of the new airport at night would reduce the impact on residents, the minister added.