Murder charges over northeastern NSW fire

A man has been charged with murder after a house fire in northeastern NSW killed an elderly woman and a five-year-old boy, and left another woman fighting for life.

The man, 60, whom police say is known to them, was assisting detectives with their inquiries into the blaze.

Emergency services found the home on Bylong Road in Tamworth engulfed by flames when they arrived on the scene at 5.30am on Thursday.

Outside the home, firefighters found a 27-year-old woman suffering "serious and significant burns" and a seven-year-old boy, with the woman informing them more people were inside.

Inside the home firefighters found the bodies of an elderly woman and a five-year-old boy.

Police were unable on Thursday afternoon to say conclusively whether the man was related to the victims found inside the house as they were still unable to confirm the identities of the bodies.

On Thursday night detectives charged the man with two counts of murder. He was refused bail and his court appearance details are being finalised.

The 27-year-old woman was transported to a hospital in Sydney in a critical condition.

The seven-year-old boy, who suffered minor burns and smoke inhalation, was taken to Tamworth Base Hospital in a stable condition.