The bodies of two Canadian sisters who died in Thailand are expected to arrive home today, a relative says.

Their uncle said that because preliminary autopsies have already been completed, Thai medical authorities have agreed to release the bodies of Audrey and Noemi Belanger.

The 20- and 26-year-old Quebec women were found dead at a beach resort in the Phi Phi islands, under mysterious circumstances.

The sisters were staying on the Thai resort island of Phi Phi, about a 90-minute ferry ride from Phuket. (CBC)

Police have said the women didn't appear to have been murdered and evidence suggests they may have been accidentally poisoned.

Their uncle, Eric Belanger, said it's unclear when the family might have a definite answer on what caused the deaths and, if it was a toxic substance, know what substance was involved.

"We don't know anything for now — and it might take a while," Belanger said in an interview.

But he said the sisters' loved ones will at least be able to receive the bodies back home, and continue the mourning process.

Belanger credited the performance of the Canadian Embassy in Thailand, saying its diplomats worked to get the bodies repatriated quickly.

He also asked the media to stop seeking interviews with the family: "I need to get through my grief, too, now that the girls are arriving," he said.

Belanger said the family is still in Quebec.

An earlier media report from Thailand had said the Canadian Embassy in Bangkok asked Thai authorities to delay autopsies on the bodies of two Canadian sisters until the arrival of their relatives.

The Bangkok Post said the embassy and relatives had asked that the post-mortems be performed at Bangkok's Ramathibodi Hospital.

Canadian officials said that report contained several inaccuracies. They said diplomats never asked anyone to delay the autopsies, said the autopsies had already been completed, and that the family had no plans to travel to Thailand.

The sisters grew up Pohenegamook, a town in eastern Quebec near the Maine border. They studied in Quebec City with their eldest sister, but worked at the family store in the community of roughly 3,000.