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.

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.

Police declined to comment on reports the death was drug-related but said it was not being treated as suspicious.

“We don’t believe she was travelling with anyone else,” a police spokeswoman told AAP on Thursday.

Police were also investigating other possible causes of death including self-harm or natural causes.

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*Featured image via Getty.