Mr Keelty has also defended the speed police reacted to last Sunday's bikie brawl at Sydney airport in which Anthony Zervas, 29, was killed.

"Machine guns at Sydney airport would be an overreaction to the current situation,'' Mr Keelty told the Channel 9 today.

"You are arming yourself for a risk that doesn't necessarily exist.''

His comments come after a call this week from former Sydney Airport boss Tony Stewart for police at the airport to be armed with machine guns to act as a deterrent.

Mr Keelty said police acted quickly after the brawl broke out between members of the Hells Angels and Comanchero gang members.

"The speed at which that event occurred ... was quite quick and the policing response was quite appropriate.''

But Mr Keelty said there is a national shortfall of policing of around 35 per cent, which is being looked at.

Another issue police are looking at is the presence of bikies within the nation's security industry.

Outlaw bikie gangs play a "significant'' role in organised crime that costs the nation $10 billion a year, Mr Keelty said.

"Because the licences in security industries are not the same across Australia it is not always possible to know exactly what the numbers are, but it is significant.''

Police will also monitor bikies wanting to come into Australia from overseas.

"People who are trying to obtain visas to come into Australia will be seriously looked at if they're coming here to commit crimes.''