A shortage of air traffic controllers caused flight cancellations and delays at Sydney Airport on Friday morning, the federal agency responsible for managing Australia’s air traffic said, as a probe into several recent near-misses on the tarmac continues.

Airservices Australia was required to enact Air Traffic Flow Management (ATFM) measures at Sydney Airport ‘due to roster constraints’ and ‘to safely manage aviation demand.’

The ATFM measures were lifted at 8.15am after conditions improved, though minor delays were expected for the rest of the morning.

‘Airservices acknowledges the ATFM measures may have caused some disruptions to airline scheduling and is working with airlines to reduce delays and the impact on passenger travel as much as possible,’ a spokesperson said by email.

The agency said it was taking steps to recruit more air traffic controllers and make it easier to call on additional staff when needed.

The shortage caused more than a dozen flight cancellations and delays of up to almost an hour-and-a-half.

Virgin Australia apologised to affected passengers, urging them to monitor their flight information on the airline’s app.

Some Qantas flights faced delays of more than an hour, ​while six flights were cancelled.

A shortage of air traffic controllers caused flight cancellations and delays at Sydney Airport on Friday

More than a dozen flights were cancelled on Friday (stock image)

Sydney Airport did not specify a reason for the delays, and a spokesperson referred inquiries to Airservices Australia.

Delays continued throughout the day in Melbourne, causing disruption to departures and arrivals, and creating a knock-on effect across the network.

The disruptions come as Airservices Australia CEO Rob Sharp and other senior executives on Friday appeared before a Senate committee examining the state of Australia’s aviation sector and its ability to deliver reliable and affordable services to regional areas.

Deputy chief executive Peter Curran told the committee there were 49 controllers employed in Sydney.

With 41 controllers needed to be operational, he added that eight or nine were currently off work due to various medical issues.

‘So when we have a bit of short term sickness like we had last night, it makes it very difficult to recover,’ Mr Curran said.

‘We were one down in the tower this morning and that led to some significant delays.’

Airservices hopes to expand its 1,100-strong workforce by 100  within the next two years.

Airservices Australia says taking steps to recruit more air traffic controllers to avoid similar delays (stock image)

Last week, a Reuters report, citing internal records and a call recording, said several air traffic controllers on duty when two Qantas aircraft nearly collided at Sydney Airport in July had been flagged as facing a high risk of fatigue.

One shift manager reportedly described the staffing situation as ‘a bit insane.’

That incident was the first of six near-misses at Sydney Airport in the space of about a month, prompting further scrutiny of air traffic control staffing amid global shortages. 

The Australian Transport Safety Bureau is investigating the close calls to determine whether they shared common safety issues or contributing factors.