An Auckland-bound Air New Zealand flight was evacuated at Melbourne airport after a white substance was found on board.
Around 20 passengers were evacuated from flight NZ124 and quarantined on Monday afternoon (local time).
An Air New Zealand spokeswoman said the flight was delayed as a result of a potential security issue.
"The flight was later cancelled as, unfortunately, the delay meant the crew had exceeded their crew hours limitation," she said.
She said the customers were being accommodated on other services and Air New Zealand apologised for any inconvenience.
Initial testing of the white powder found that it was not poisonous, Newshub reported.
The Melbourne Fire Brigade (MFB) Hazmat crews responded to the incident.
"Crews were alerted to the incident just after 1.30pm after three grams of an unknown powder was located in the overhead luggage compartment," a statement from MFB said.
"Firefighters donned chemical splash suits and entered the aircraft and took a sample of the substance for testing."
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