Australian federal infrastructure minister Anthony Albanese says a second airport is needed urgently in Sydney.
"The airport is more congested than it was a year ago, the growth is enormous and the delays have increased," Mr Albanese said in an address to the Sydney Institute on Monday night.
"The land size is one third the size of Brisbane and half the size of Melbourne, so you don't have an ability to grow on site."
He said the argument that you can allow more planes to take off each hour would cripple the airport.
"Sydney Airport is now struggling to cope with 80 movements per hour," he said. "It is now the worst performing capital city mainland airport.
"In terms of the delays that are there, there's only so much you can squeeze out of something.
"And it is at breaking point, which is why the solution is - in my view - very strongly a second airport."
AAP reports New South Wales Premier Barry O'Farrell has suggested connecting Canberra airport with Sydney via high-speed rail instead.