An 11-year-old boy and his father are dead and a woman is in a serious condition following a suspected gas leak from a fridge inside their tent on a remote beach north of Perth.

Key points: The man and boy were on a family camping trip south of Wedge Island

The man and boy were on a family camping trip south of Wedge Island It is believed fridge leaking gas inside the family's tent caused their deaths

It is believed fridge leaking gas inside the family's tent caused their deaths Premier Mark McGowan has described the incident as a terrible tragedy

Police and rescuers arrived on the beach on Monday about 8 kilometres south of the Wedge Island access road, about 150 kilometres north-west of Perth, after receiving a report a child was not breathing.

Emergency services personnel found the bodies of the boy and a man aged in his 40s, while the family's dog was also found dead.

A woman aged in her 40s and believed to be the man's wife was "in need of urgent medical assistance", WA Police said.

A rescue helicopter airlifted the woman to Royal Perth Hospital, before she was later transferred to Fiona Stanley Hospital, where she remained this morning in a serious but stable condition.

It is believed the alarm was raised by friends of the family who were on the camping trip with them and went to their tent after they failed to wake up in the morning.

WA Police said the deaths were not being treated as suspicious.

Other families are believed to have been camping on the beach nearby when the tragedy unfolded. ( ABC News: Eliza Borrello )

"Initial investigation at the scene suggests there may have been a fault with an item of camping equipment located inside the tent the family were sleeping in," police said in a statement.

"This aspect of the investigation is ongoing."

Fridge used inside tent blamed for deaths

WA Police Minister Michelle Roberts said the incident, coming at the end of the Australia Day long weekend was "very disturbing".

"I understand there may have been some kind of gas leak from a fridge that was being used in the tent," she said.

"It is just very tragic. It is a long weekend, so many people would have had a similar experience of camping, be it at Wedge Island or somewhere else, and they would have used potentially similar equipment.

"So there really does need to be a thorough investigation into how this occurred."

Michelle Roberts says the deaths were a tragic accident. ( ABC News: Andrew O'Connor )

Premier Mark McGowan has described the incident as a terrible tragedy.

"It's very, very sad and very tragic for everyone involved. The man's wife is in a serious condition. For everyone involved it is a shocking situation," he said.

Police said the Department of Fire and Emergency Services attended the scene to help with "the safe removal of the camping equipment".

"Police would like to speak to anyone who was camping in the area at the time, and who have not already spoken to police," they said.

Wedge Island residents lend a hand after tragedy

Wedge Island local Roslyn Smith said the community had banded together to provide help the two other families who were on the camping trip.

"We said 'look, you can stay the night if you need because it's dark and [there are] kangaroos'," she said.

But she said they had been eager to return home to Perth to be with relatives and friends.

Locals also lent their vehicles to emergency personnel to help them access the beach.

Police found the bodies of the man and boy on the the beach near Wedge Island on Monday. ( ABC News )

"We had to take them in our four-wheel drives because they had no cars that could get down there," Ms Smith said.

The president of the local Shire of Dandaragan, Leslee Holmes, said the deaths were awful.

"It's dreadful … you think of these weekends of everybody having a good time, spending time with their family, kids running around and having a ball and then you have a tragedy like this that's quite unexplained," she said.

She said the family was camping in an isolated area with limited access.

"You're not [supposed] to camp there, there are signs and everything, but unfortunately they may not have seen them and they've been probably fairly away from everybody," she said.

A report will be prepared for the coroner.

Wedge Island has been home to holiday and fishing shacks since before World War II. ( Facebook: Preserving Wedge and Grey for WA )

The peninsula on the mainland adjacent to Wedge Island is home to a historic shanty town settlement that pre-dates WWII.

While camping is not permitted in many areas on the mainland, it is a popular holiday destination with tourists and West Australian families.