Qantas has been forced to ground one of its jets after rats were found on board.
Flight attendants discovered five rats in the cabin of a Boeing 767 Monday as they were preparing for take-off from Sydney Airport, Sky News reported.
The rats were found in emergency medical equipment just before passenger were due to board.
The passengers, who were bound for Brisbane on the 5pm flight, were moved to another flight while the rats were killed and engineers checked if they had damaged any wiring.
Qantas is unsure how the rats got onboard.
"We still don't know how they got on board but it is obviously not a common occurrence,'' a Qantas spokesman said.
A Qantas spokeswoman said the airline was currently investigating how the rats came to be in the plane but described the incident as "unusual''.
Engineers who inspected the plane on Monday found no damage had been caused to the plane's wiring systems.
The aircraft was due to return to service this morning, the spokeswoman said.
While not a common occurrence, it's not unheard of to find rats or other pests on planes. In April health inspectors found rodent droppings "too numerous to count" near a Delta Airline jet's food and drink storage area.
In February last year hundreds of passengers were ordered off an Air Canada flight bound for London from Ottawa after a huge rat was discovered on board.
Rats aren't the only creatures to invade jets - a colony of cockroaches was discovered in the first class section of an American Airlines flight last March