Medicals for older divers are needed and Australian standards should be reviewed after six diving and snorkelling deaths in five days, one expert says.

Three tourists died in Queensland on Wednesday and Friday, a Tasmanian man died on Saturday and a New South Wales man and a Victorian man died on Sunday.

The Australian Underwater Federation president, Graham Henderson, said the number of deaths in such a short period of time was unusual.

He also said the diving industry is ageing, with older people now having the will and money to take it up as a hobby, and there was a concerning variation in dive course quality.

“To be honest some of the courses that are run ... are pretty minimalistic,” Henderson said. “The Australian standards need to be looked at and talked about more.

“Probably an age requirement to have a diving medical. That would be something that would be well worthwhile.”

Henderson said people were moving away from diving and snorkelling in large groups or clubs, which increased the danger of something going wrong.

The AUF is the government-recognised body for amateur underwater activities.

A NSW man in his 40s was snorkelling with two people when he got into trouble and was assisted on to a boat off Congo around 10.30am on Sunday. Paramedics tried to revive him but he died at the scene. Another man who was scuba diving with his friends in Victoria on Sunday died after he was reported to be in distress.

A 49-year-old Tasmanian man died while diving on Saturday afternoon, while a 60-year-old Englishman died during a Queensland diving trip on Friday.

French tourists Jacques Goron, 76, and Danielle Franck, 74, died while snorkelling on Michaelmas Cay, north of Cairns, on Wednesday.