Sydney Airport is facing renewed aviation safety scrutiny after authorities began investigating a third near-miss involving aircraft in less than three weeks.

The latest incident occurred on Sunday when a Virgin Australia Boeing 737 was cleared for take-off while a Qantas Boeing 737 began crossing the runway. The Virgin aircraft stopped its take-off after the crew identified the Qantas aircraft crossing ahead.

The Australian Transport Safety Bureau is investigating the incident as part of its examination of recent runway safety events at Sydney Airport.

The latest incident follows another event earlier on the same day involving a Jetstar aircraft and a Qatar Airways aircraft on the airport's taxiway. A separate runway incursion involving Qantas aircraft occurred on 27 July.

The series of incidents has increased attention on air traffic control operations and staffing at one of Australia's busiest airports.

Airservices Australia has acknowledged challenges involving experienced air traffic controller numbers. The organisation has been working on recruitment and training as aviation activity continues to grow.

Sydney Airport is an important international and domestic aviation hub, handling large numbers of passenger flights every day. Safe coordination between aircraft, ground operations and air traffic controllers is therefore critical to maintaining the network.

Investigators will examine the circumstances surrounding the latest incident, including communications, runway clearances and the sequence of events that resulted in the two aircraft being on the runway at the same time.

The incident did not result in a collision, and the aircraft maintained separation. However, aviation investigators are examining the event because of the potential safety implications.

The investigation comes at a time when Sydney's aviation environment is becoming increasingly complex, with the opening and operation of Western Sydney International Airport adding another major airport to the region's aviation network.

Authorities are expected to use the investigation findings to determine whether changes are required to improve operational safety and reduce the possibility of similar incidents occurring again.

The repeated incidents have also prompted questions about staffing, workload and the systems used to coordinate aircraft movements around Sydney Airport.