The deal, the biggest trade sale in Australian history, gives the Southern Cross consortium full control of Sydney Airport Corporations, the airport's managing company, and the first right to build a second Sydney airport.
Southern Cross, which beat off two other bidders for the airport, also includes German construction company Hochtief and the Commonwealth Bank of Australia.
The government has already sold the country's other major airports, in Melbourne, Brisbane and Perth.
But Sydney is the nation's largest, having served about 26 million passengers last year.
Big deal
The deal was originally launched last summer, but the government delayed completion amid uncertainty after 11 September.
Despite the lingering uncertainty in the airline industry, the price achieved was considerably higher than expected, possibly reflecting the booming Australian economy.
Nicholas Moore, head of Macquarie's Investment Banking Group, said passengers would see very little change to the airport, at least in the short term.
Southern Cross is considering tweaking the airport's retail area, and plans to widen runways to accommodate more modern aircraft.
The airport sale is one of the last stages in the government's ongoing privatisation programme, with funds raised earmarked to pay some A$4.2bn its A$40bn debt.
Now, the Australian government owns only two significant corporate assets - a 50.1% stake in dominant telecom firm Telstra and all of the country's largest private medical insurer, Medibank Private.
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