Canberra Airport chief executive Stephen Byron has backed Premier Barry O'Farrell's call to expand the capital's terminal and build a high-speed rail service between Sydney and Canberra to ease the pressure off Sydney Airport.

Mr O'Farrell has rejected the federal government's proposals for a second Sydney airport at Badgerys Creek or Wilton, but Mr Byron said the Premier's preferred option may be lost if plans for 1850 new homes south of Queanbeyan go ahead.

''This is pretty critical for him, because without this he doesn't have a solution to Sydney's airport problems,'' he said.

''We think we're a good option, we think we're the right option, but we're only an option if we don't have houses under the flight path.''

But Village Building Company chief executive Bob Winnel said the proposal was not under any current or proposed flight path.

He said the company's current proposal, which would include a two-kilometre wide corridor through the entire area, did not threaten to put any constraints on Canberra Airport.

''I have no idea why the airport is making a grab for land,'' he said. ''It's a very bold and rapacious move to sanitise huge tracts of land.''

Mr Winnel said the proposal was fully compliant with Australia's stringent aircraft noise exposure forecast system, but was being singled out due to the ''successful propaganda of the Canberra Airport and the support it receives from Minister [Anthony] Albanese''.

''It's inexplicable that for over 30 years every major development that has been compliant has been approved,'' he said. ''Tralee is the first and only one to be treated differently.''

Mr Winnel confirmed the proposal approximately 10-12 kilometres from the end of the runway included a long-term plan to build 5500 homes.

Planning Minister Brad Hazzard is expected to make a decision within two to three weeks and Jerrabomberra Residents Association president Michael Ziebell said it should not be influenced by Mr Byron's concerns.

''The airport has tried every trick in the book to make sure this doesn't happen,'' he said.

''Minister Hazzard has all the information and the second Sydney airport is just a bit of a furphy. It shouldn't persuade him in any shape or form.''

If built, the high-speed rail link would cost the same amount as an airport and would transport passengers between Sydney and Canberra within an hour.

Mr O'Farrell said he wouldn't change his opposition to a second Sydney airport.

with AAP