A Qantas captain has reportedly been forced to leave the cockpit only moments before taking off after the crew suspected she had been drinking.

Fairfax reports the incident occurred last Monday when a Qantas 767-300 aircraft was due to fly from Sydney to Brisbane.

The plane had already pulled away from the domestic terminal with 254 passengers on board and was taxiing towards the runway.

Flight attendants on the aircraft reportedly informed the flight operations managers that they suspected the senior pilot had been drinking.

Qantas management made the decision to stand down the Captain from command and return the plane to the gate.

According to Fairfax, the pilot recorded a positive reading for alcohol but the airline wouldn’t comment how recently she had been drinking.

Qantas does not allow their pilots to have an alcohol reading of any level when they take control of a plane.

The investigation into the incident is expected to take at least a month.

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