A British man has died after being bitten by a sea snake while working on a fishing trawler off the Northern Territory coast.

Key points: The man was bitten while pulling up a net on a boat off Groote Eylandt and died on board

The man was bitten while pulling up a net on a boat off Groote Eylandt and died on board NT WorkSafe is investigating the incident

NT WorkSafe is investigating the incident The British High Commission has been informed of the man's death

Northern Territory Police said the 23-year-old was bitten while pulling up a net about 12:00pm on Thursday, about 70 nautical miles south of Groote Eylandt.

A CareFlight helicopter crew and ships in the area rushed to help but were unable to save the man.

Craig Garraway from St John Ambulance said there was little emergency services could do to help the man.

"A trawler off Groote Eylandt had reported that one of their male crewmen had been bitten by a sea snake," Mr Garraway said.

"The Groote Island health clinic and police responded to the trawler, but unfortunately the male passed away at some point [Thursday] afternoon."

The man was declared dead after the trawler arrived at the town of Borroloola in the Gulf of Carpentaria.

The British High Commission has been informed of the man's death.

Police are investigating and a post-mortem examination will be carried out.

NT WorkSafe said in a statement it had been notified of the man's death and had begun an investigation into the incident.

It is not the first death involving a young British man aboard an Australian fishing boat in the north.

Twenty-year-old Ryan Donoghue was electrocuted on a prawn trawler in the Gulf of Carpentaria in November 2013.

NT Coroner Greg Cavanagh found his death was needless and a tragic waste of young life.

"It would have been prevented if there was even a modicum of compliance with the law," Mr Cavanagh said.

Map Groote Eylandt map

Sea snakes 'equally poisonous' as tiger snakes

Earlier this year, Darwin fisherman Peter Davis nearly had his finger amputated after being bitten by a sea snake that was snagged on his line.

Sea snakes are "equally poisonous if not more poisonous as things such as our tiger snakes and western brown [snakes]", Charles Darwin University honorary fellow Dr Michael Guinea said at the time.

While sea snakes were rarely aggressive underwater, if caught by a fisherman Dr Guinea said cutting the fishing line could be the safest option.

Anyone bitten by a sea snake should bandage the wound and immobilise it, before seeking medical attention, authorities advise.