Building forecaster with BIS Shrapnel Kim Hawtrey said Badgerys Creek would likely focus more on cargo than Kingsford Smith Airport including a significant freight now coming by air into Canberra from Melbourne.

Dr Hawtrey said, in the short term, Badgerys Creek's development was not going to help Canberra's position.

Badgerys Creek would experience a rapid rise of new industrial buildings, warehouses and transport centres close to the new airport and spreading out over a five to 10 kilometre radius.

While the airport would take 10 to 15 years to build, the property market would anticipate this development from an early stage.

"People will start planning ahead," Dr Hawtrey said. "Land purchases will be the first thing, future developers, potential users like supermarket chains, Woolworths and Coles who have a higher need for warehousing and logistics, they'll be thinking strategically early on, they will be buying up land and looking to build and develop on that land as the opening of the airport draws closer."

The NSW government proposed a ministerial direction last year which would have banned increased residential density and developments such as child care centres, schools and health services, to protect Canberra Airport's curfew-free status. But it is yet to implement the policy.

The "Section 117 Direction" would have limited 750 properties in surrounding local government areas including Queanbeyan within the (noise contour map) ANEF 20 to existing development rights only.

Last month, the Member for Monaro John Barilaro declined to comment. But on Wednesday he said the Badgerys Creek decision strengthened his argument the ministerial direction was not needed.

"Badgerys Creek was always going to be Sydney's second airport, Canberra will be an international airport to a degree, its own masterplan allows that to happen," Mr Barilaro said. Pre-sales of residential blocks at Tralee and Googong had ideal growth, and scrapping the Section 117 would enable people to subdivide farms for redevelopment.

Canberra Airport managing director Stephen Byron said the restrictions should still go ahead, despite Badgerys Creek's development.

"In fact, you will note the Prime Minister highlighting the low number of houses around Badgerys as being a key reason for it to have no curfew and also the role NSW government planning controls have played in preventing new residential," Mr Byron said.

"So the proposed 117 Direction for Canberra Airport is entirely consistent and Badgerys Creek highlights its necessity."

NSW Upper House MP Steve Whan and Queanbeyan Mayor Tim Overall say the likelihood of freight operations out of Canberra are now more remote since the second Sydney airport announcement.

"For this area, finally getting certainty over Sydney's second airport can let everybody, including Canberra airport, go ahead with planning what is a realistic level of business for them," Mr Whan said.