Staff found the 20-centimeter (8-inch) Mandarin Rat Snake in the passenger cabin near the door late Sunday before passengers were due to board the flight bound for Tokyo from Sydney International Airport, Qantas said in a statement.

Australia's flagship airline said passengers were given hotel rooms overnight and left Sydney on a replacement plane Monday morning. Qantas said the original jet would be fumigated before returning to service in case there were other snakes on board.

The snake was taken by quarantine officials for analysis.

The Agriculture Department said the snake, a species that grows to an average 1.2 meters (4 feet), had been euthanized, "as exotic reptiles of this kind can harbor pests and diseases not present in Australia."