Friends of Australian man shocked he killed his kids in Bali

Bali police say Damien Shaw killed his children and himself at their Kuta home. (Supplied: Indonesian police)

Friends of Damien John Shaw have described their shock and horror after the Australian man apparently killed himself and his two children at their Bali home on Sunday.

WARNING: This story contains graphic descriptions some readers may find distressing.

Bali police are investigating what they say is a double murder-suicide, after the bodies of the 56-year-old and his six-year-old son and four-year-old daughter were found inside their bungalow in the popular tourist resort of Kuta.

Denpasar City police have interviewed the children's mother, who was in Jakarta with family when the attack unfolded.

She had called a neighbour to perform a welfare check on her family, after she said a call to her husband disengaged and she heard one of her children crying.

Denpasar City police said an autopsy would not be carried out on the children at the request of their mother.

"Initial external findings suggest the two children died as a result of acts of violence," the police said in a statement.

Police say the children died at their home at the hands of their father. (Supplied: Indonesian police)

Police said Mr Shaw died by suicide.

"From the CCTV there is no indication of another perpetrator," Chief Commissioner Leonard Simatupang said.

He said CCTV had recorded the children screaming.

Mr Shaw's wife told police she had filed for a divorce in 2022.

"The reason was that the husband is temperamental, but later she revoked the case as the husband was showing improvements," Chief Commissioner Simatupang said.

"There is no medical psychiatric record about the man; it had only come from the wife's statement that the husband is temperamental and having high anxiety."

Bunbury resident Tania Dagnall said she and her husband had been friends with Mr Shaw for the past 11 years.

She said they had caught up with the man they called "Damo" just three months ago in Bali and immediately noticed his "gaunt" appearance.

Damien Shaw, 56, used to work in the oil and gas industry. (LinkedIn)

"I was shocked looking at him; he didn't look like him when he walked up and joined us for coffee … he was not the buff dude I was used to seeing," she told the ABC.

"If he has done this, there's no excuse for it, never any excuse for that, ever.

Ms Dagnall said she was sad that Mr Shaw had not reached out to them.

"We could have been on a plane," she said.

The ABC understands Mr Shaw was originally from Perth but had lived in Bali for decades and had converted to Islam when he married his wife about six or seven years ago.

To comply with his adopted faith, friends say he stopped drinking alcohol and did not touch drugs.

He previously worked as an able seaman in the oil and gas industry, but retired from this fly-in, fly-out role to spend more time at home, Ms Dagnall said, often taking the children to school and swimming lessons.

"We honestly thought he was living the life, retire to a beautiful place, have a couple of kids," she said.

Mr Shaw had several properties in Perth and overseas, including a house in Japan, Ms Dagnall said, which he used as a base for snowboarding.

Despite being financially stable, Mr Shaw's marriage had become tense in recent months, friends say.

They cannot comprehend how he could have murdered his children.

"I can't understand why he would have done such a terrible thing. It just breaks our hearts," Ms Dagnall said.

Police said Mr Shaw's body was being examined at Sanglah Hospital.

Meanwhile, officers are continuing the forensic processing of the crime scene and reviewing CCTV footage from inside and outside the property.