Air traffic controller shortage 'happening frequently
Source: ABC News Online
Airlines and pilots were told they would have to navigate themselves if they wanted to fly through air space north-west of Canberra between 8:00pm and 10:00pm (AEST).
Qantas says its planes were diverted and there were delays of up to one hour.
Civil Aviation Safety Authority (CASA) spokesman Peter Gibson says the shortages are happening because of a lack of controllers worldwide.
"It is happening reasonably frequently," he said.
"The Civil Aviation Safety Authority is getting weekly reports on this.
"It's caused by a shortage of controllers usually triggered when some controllers can't come on for a shift due to sickness.
"We're monitoring it very carefully to make sure that all the appropriate safety standards are being met. We're satisfied that it is being managed properly."
Mr Gibson says new controllers are being recruited but training takes two years.