But the family has been told toxic fish may have been the killer.
Noelene Bischoff, a senior nurse from the Sunshine Coast, and her 14-year-old daughter Yvana died in the early hours of Saturday, less than a day after they checked in to their beachfront resort on Bali's east coast.
Grieving relatives in Australia say the Department of Foreign Affairs and Trade (DFAT) has told them toxic food caused the deaths.
"We've been told it is fish they've eaten," Ms Bischoff's brother-in-law Kevin Bowe told the ABC.
Noelene's mother Jean told Network Ten: "It's a blessing to us that they've been taken together because one couldn't have coped without the other."
A school project prepared by Yvana last year depicts an animal-lover with big dreams.
"I have one horse and love to ride. My favourite food is mango or anything chocolate," she wrote.
"My hopes ... I want to be an equine vet."
Local sources told AAP on Sunday night they were yet to confirm a cause of death as they were still waiting for permission to proceed with the autopsy.
Under Indonesian law, an autopsy can proceed without permission from Tuesday.
However, the sources said a search of the hotel room where the mother and daughter were staying had not revealed any sign of violence.
They also said investigators had interviewed witnesses from the hotel, a clinic and a restaurant in Ubud where the pair ate dinner.
Padang Bai Beach Resort staff were alerted early on Saturday morning when Yvana asked for help, telling security guards she and her mother had fallen gravely ill.
The pair were taken by private ambulance to a nearby medical centre but about 1.45am local time the mother died, according to local sources.
The girl was rushed to BIMC Hospital, an international clinic in the Balinese capital of Denpasar, but could not be saved.
Medicine found in the Bischoffs' hotel room is being tested.
One senior local police source told AAP on Saturday the treating doctor at the first clinic suspected a food allergy.
"What kind of food, we don't know," he said then.
