The brother of a Queensland mother who, along with her daughter, died from food poisoning in Bali says it is unlikely the pair would have survived had they contracted the illness in Australia.

Autopsies on the bodies of Noeline Bischoff, 54, and her 14-year-old daughter Yvana have shown they likely died from a rare form of food poisoning after eating fish in a Bali restaurant, according to the family.

Ms Bischoff’s brother Malcolm Bischoff told ABC Radio it’s believed a rare bacteria caused what’s known as “scombroid poisoning”, and the fact both mother and daughter also suffered from asthma may have contributed to the severe reaction they had.

He said the doctors who conducted the autopsy – which the family pushed to be held in Queensland – were “stunned” by the finding. “It’s just one in millions of chance that that could all come together for that to happen with two people at the same time,” he said.

“There’s a few governing factors. The age of the fillet and also the handling through filleting. Any part of the fillet that is close to the intestines could have a greater concentration of this scombroid bacteria.

“It is also possible that other people ate pieces of the fish further away from that that may have been fine.”

Mr Bischoff said he originally suspected foul play, saying he thought it didn’t make sense for two people to die of food poisoning in such similar circumstances.

However, he said doctors believed the bacteria was so rare Noeline and Yvana would probably not have survived if they had contracted scombroid poisoning in Australia.

“More than likely it wouldn’t have been diagnosed here anyway, so more than likely the same result would have happened,” he said.

Mr Bischoff called on the federal government to update its travel advice to Bali, to warn of the risk of food poisoning.

However, he stopped short of blaming the Bali restaurant for the death of his sister and niece.

“Any overseas travel in a third world country is dangerous to some point,” he said.

“It’s probably just the luck of the draw who gets what where.

“It is one of those things that it is a lucky dip, I suppose.”