A weekend house fire in Sydney that killed two women has been deemed an accident.

Catherine MacKenzie, 81, and her daughter, Frances MacKenzie, 53, died in the early-morning fire Sunday at 95 Edgewood Dr., in Sydney's Hardwood Hill area.

Deputy Fire Marshal Vince Penny said the fire began on the patio deck and spread into the building through some open basement windows.

"It is a fire that has no malicious cause to it," he said Monday. "It is an accidental-type fire."

A neighbour discovered the blaze around 3 a.m. By the time police and firefighters arrived, one side of the building was engulfed in flames.

Rescuers forced their way in after hearing children calling for help.

Two children, ages 6 and 10, suffered smoke inhalation. They remain at the IWK Health Centre in Halifax in fair condition, a hospital spokesperson said.

Penny said it was lucky the children survived.

"It's unfortunate that we lost two individuals, but also it's very fortunate that there was two young children that were saved as a result of the action of the police and the Sydney fire department," he said.