Sydney - A teenager was fighting for his life on Tuesday after accidentally drinking a deadly box jellyfish tentacle left in a jar of water in a surf club refrigerator, an ambulance spokesperson said.

The 17-year-old lifesaver from the resort village of Mission Beach in northern Queensland state drank water from a glass jar containing box jellyfish tentacles on Monday afternoon. The tentacles apparently were being saved to give to university researchers.

The victim, whose name was not released, swallowed at least one mouthful of water before realising his mistake and alerting his colleagues.

A Queensland Ambulance Services spokesperson, speaking on customary condition of anonymity, said he was having trouble breathing when ambulance officers arrived about 10 minutes later.

Deadly box jellyfish infest northern Australian coastal waters from October to April every year.

The Australian Institute of Marine Science warns box jellyfish stings are usually fatal to swimmers.

"If you are stung, your chances of survival or getting to shore are virtually zero," the Aims Internet web site said.

"The pain has been described as so excruciating you will probably go into shock and drown even before the full effect of the venom takes place," it said. - Sapa-AP