Derek Kehler and Helena Curic were killed as they slept in a converted shipping container. It is believed they were poisoned by carbon monoxide from an open fire.

Outpourings of grief have been shared by the family and friends of the young couple who were poisoned by carbon monoxide as they slept in a makeshift cabin in Australia.

Derek Kehler, 32, and Helena Curic, 31, are believed to have suffocated in their sleep as a woodchip fire burned through the night in the converted shipping container on what was meant to be an idyllic long weekend with family.

At about 7.30am the next morning, Curic's sister Natalie found the couple as they lay in the cabin on the Kurrajong property, about 75km north west of Sydney.



She called for help, but the paramedics could not revive them.



Curic was a marketing and design manager at a Sydney graphic design company and Kehler was a country music singer from Manitoba in Canada who went by the stage name Steel Audrey.







The pair met in Canada years earlier before settling in Australia.



Kehler's mother posted a photo of her son to her Facebook page hours after the tragic deaths.



"Always in my heart xx" she posted from her home in Manitoba according to her Facebook page.



Several friends of the pair had posted condolence messages.



"My heart is breaking," read one message under a photo of Kehler.



Police Inspector Suzanne Rode-Sanders said there was no ventilation in the cabin and believed the pair had died in a terrible accident.

The campsite where the Sydney couple died.

"[It's a] horrific incident especially for one of the relatives to walk into," Rode-Sanders said.

Police said it was a tragic reminder of how careful people needed to be with open fires and electrical heating.

"It appears they had some kind of makeshift heater inside the cabin and there wasn't any ventilation and as a result they may have asphyxiated carbon monoxide poisoning," she said.

"Our thoughts go out to the family, it's very very tragic."

It is understood the family were camping on the rural property for the long weekend, and were sleeping in three steel shipping containers that had been converted into cabin-style accommodation.

Curic's sister Natalie, her partner, and two children were believed to have been sleeping in one of the other steel containers close by. On Monday morning, remnants of the previous night's campfire dinner - camping chairs, a wine glass and cooking utensils - sat abandoned next to a fire pit.

"[The family] are quite devastated ... very, very emotional and upset."

Rode-Sanders hoped more deaths would be prevented.

"I just think that we always have to be mindful that when there is any sort of open fire it creates fumes and we need to have ventilation."

Police have set up a crime scene and forensic police will examine the area.

Stephen Bellamy, who has lived in Kurrajong for 30 years, said there were a couple of cabins in bushland where the police had gathered.

He said he was shocked to hear of the deaths.

"I always tell people, whatever you do, if you have anything going in the house, always leave a window or a door open where you are. It may be a bit chilly but ... it's dangerous," he said.

"That's a terrible thing to happen.

"[I'm] rather shocked up here, because it's such a simple thing that can happen."