A Senate estimates committee today heard details of air traffic control towers left understaffed and at times unstaffed because of sickness and a lack of controllers.
"We do have a shortage of air traffic controllers," the general manager of air traffic control for Airservices Australia Jason Harfield told the hearing.
"One of the factors that exacerbates our problem is that it takes at least two years from somebody off the street to be qualified as an air traffic controller.
"We have had a number of service interruptions, particularly over the last six to 12 months."
For example, he said, last Friday between 2.30pm (AEDT) and 6pm, and from 9pm until midnight, there was only one air traffic controller on duty for Sydney arrivals from Melbourne, when normally there were three people available.
Mr Harfield said that was not quite accurate but services had been delayed because of staff sickness.
"The situation was managed so that the service could be provided," he said.
"There were restrictions placed on how traffic would flow through the airspace to ensure that the system wasn't overloaded and provision was made to provide breaks to the controller."
Senator O'Brien continued his line of questioning, asking about closures at the Launceston air traffic control centre last weekend.
"Launceston tower closed early Sunday night," he said.
Mr Harfield admitted he was unaware of the closure at Launceston.
"It did open late on Sunday, that was a result of the morning shift at Launceston tower going sick and we were unable to get a replacement staff member.
"At the moment staff members at Launceston, the normal establishment is six."
Mr Harfield said one person working at Launceston was on long-term sick leave.
"We've just gone through a selection process to find a replacement."