The immigration department is unsure how long it will take to manage a special humanitarian intake of 12,000 refugees from Syria.
So far only 26 Syrians have been resettled in Australia but 200 others have been granted visas.
A further 7416 people are in the pipeline awaiting health and security checks, a Senate estimates hearing was told on Monday.
Immigration department secretary Michael Pezzullo said the program would be delivered over a number of years and the security assessment process could not be rushed.
"There will be nobody getting in under the radar," he said.
Mr Pezzullo acknowledged public concerns about terrorism.
"We are alive to the possibility of terrorists attempting to get through by this means," he told the hearing.
"Certainly infiltration by Daesh or Islamist fighters is very high on our priority for screening."
Of the annual refugee intake of 13,750, 4850 places had been earmarked for Syrians and Iraqis and would be delivered by the end of June.
The separate 12,000 intake runs parallel.
Share
