Hundreds of passengers scheduled to board an Australian Qantas jet were forced to spend a night in hotels after a tiny snake was found on the door of the aircraft.

The reptile was discovered on board the Tokyo-bound aircraft at Sydney International Airport yesterday night.

Twenty centimetre long and thin as a ball-point pen, the snake was found wriggling near the plane's door, media reports said today.

Qantas spokeswoman said a cabin crew discovered the critter as some 370 passengers was about to board the plane.

The passengers spent the night in nearby hotels while quarantine officials caught and examined the snake.

The plane had been on ground in Sydney all day after an earlier flight from Singapore.The re-scheduled flight took off at 7.15 am on Monday.

In January, a three metre python was discovered in an early morning Qantas flight from Cairns in Queensland, Australia to Papua New Guinea.