The death of an Australian woman on an international flight that landed in Sydney is not being treated as suspicious amid reports the passenger was a suspected drug mule.

Emergency services were called to Sydney International Airport about 6.50am on Thursday after staff requested assistance for a 42-year-old woman who had died on a Delta flight from Los Angeles on its way to Perth.

Delta Air Lines said it was "sorry" for what the Schears' family went through. Credit:AP

Passengers were left waiting for more than 90 minutes on the tarmac as police boarded the plane and established a crime scene.

It was suggested the woman might have been a drug mule, according to 2GB Radio.