It's the baggage with bite - a crocodile on the loose in the cargo hold of a Qantas aircraft.

Qantas has confirmed a crocodile escaped from its cage during a flight between Brisbane and Melbourne.

Although the jaws of a crocodile could have been a nasty find for the baggage handler who discovered it was on the loose, the reptile was safely re-captured without drama.

A Qantas spokesman confirmed the incident happened last Monday.

He was unsure of the crocodile's size, but said it "was not fully grown".

The airline and cargo handling company Australian Air Express has launched an investigation into how the crocodile got out of its cage and whether it was loaded correctly.

"The animal was quickly and safely secured when the aircraft arrived in Melbourne," the Qantas spokesman said.

"The investigation is focusing on whether it had been loaded appropriately on delivery to Australian Air Express."

Australian Air Express has been sought for comment.

- Sydney Morning Herald