A study of the Australian government's preferred site for a second airport for Sydney has raised concerns that it may have to consider an alternative location soon before the existing airport reaches capacity limits in the coming years.
The study, conducted by the Department of Infrastructure and Transport, says that Sydney airport's peak hour slots will be fully allocated by 2015, and that by 2020, there will be an inadequate number of parking bays and aircraft stands to load and offload passengers.
It adds that by 2027, available slots across all hours of the day will be allocated and beyond 2033, "demand across all operating hours will be unmet".
To meet those challenges, the government has advocated building a second international airport at Wilton, southwest of Sydney's central business district, which would be operational by 2045 when Sydney will have reached saturation point.
The study found, however, that the Wilton site "will be environmentally challenging to build".
It says that the site would require extensive earthworks and clearing, and that mine subsidence from nearby coal seams "poses a major safety risk for any future development".
In addition, a number of likely protected species were found on the proposed site, which will require "extensive environmental assessment and appropriate mitigation".
Transport minister Anthony Albanese says that the government will now move forward and conduct a geotechnical analysis on the Wilton site.
The report also considered a proposal to open Royal Australian Air Force Base Richmond, located west of Sydney, to civilian traffic as it can handle up to 5 million passengers annually.
Albanese says that the government will commence discussions on opening up Richmond, but says "it will not stop the need for a greenfield site for Sydney's second airport".
"Sydney needs a second airport sooner rather than later and there are limited options for a greenfield site," he adds.
In 2012, Sydney airport handled a record 36.9 million passengers, an increase of 3.6% year on year.