Updated | Son, 46, arrested over deaths of parents in Sutherland home

A man is expected to be charged with two counts of murder in a beside court hearing on Wednesday after his parents were found dead in their Sutherland home.

David Reid, 46, who lived with his parents Diana and Victor (Graham) Reid all his life in their Tudar Road home, was moved late on Tuesday from Sutherland Hospital to a secure unit at Prince of Wales Hospital.

David Reid is reportedly being treated for non-life threatening, self-inflicted stab wounds.

He called police about 8.30am on Tuesday, threatening self harm.

When police arrived at the home, they found the bodies of his parents in a bedroom and living area of the house.

Update

The couple found dead in their Sutherland home have been named as Diana and Victor (Graham) Reid.

Their son David, 46, who lived with his parents all his life, is the man who was arrested by police at the house in Tudar Road.

He was taken to Sutherland Hospital for treatment of non-life threatening injuries and is expected to face court on Wednesday.

Lyn Howard, a close friend of Ms Reid and neighbour for 50 years, told the The Sydney Morning Herald as she left Sutherland Police Station after making a statement, "It's terrible. I'm not quite with it at the moment".

"It was horrendous. We couldn't get out of the house, couldn't get up the street. Then the detectives turned up, Polair was up there ... It was pretty grim."

Mr Howard added that it "wasn't until the dogs started making a bit of noise, from all the voices outside that ... we knew something was wrong."

"When they took him they put him into an ambulance, he was handcuffed then ... otherwise he just had a pair of scungies on, but he must have been sitting there like that for an hour."

Earlier, Mr and Mrs Howard said they heard no disturbances coming from the Reid home.

Update

Police are continuing to interview a man after his parents were found dead in their Sutherland home.

"While formal identification is yet to be completed, the deceased are believed to be the man's 71-year-old mother and 75-year-old father," a police spokesman said.

The spokesman also said the couple had "each sustained a number of injuries", contrary to earlier information.

"The man has been taken to hospital under police guard for treatment of non life-threatening injuries," the spokesman said.

"A crime scene has been established at the house and is being examined by specialist forensic officers."

Update

A man being questioned over the deaths of a couple in their 70s at Sutherland is believed to be their son.

Sutherland Police Area Commander, Detective Superintendent Jason Box, said police went to a house in Tudar Road after receiving a call about 8.30am today from a man threatening self harm.

"Police were allowed entry by the occupant, a 46-year old-male," Mr Box said.

"When they went inside they found a male and female, who appeared to be deceased, in separate locations in the house."

Mr Box said the 46-year-old man was taken into custody.

"It is not confirmed, but we believe they are his parents," Mr Box said.

Mr Box said police were not aware of any mental illness of the man in custody.

"We understand the couple have lived there for a considerable time, and that the man lived with them," he said.

"There is another son, who has been informed.'

Mr Box said there was no indication of the cause of death of the couple, or what led to the tragedy.

There were no signs of violence "as far as we are aware," he said.

Mr Box said the investigation was at an early stage and they hoped to get more answers quickly.

Earlier

A man has been arrested following the deaths of two people at a home in Sutherland this morning.

Just after 8am, emergency services were called to Tudar Road, following a concern for welfare.

Police found the bodies of a man and woman, and arrested a 46-year-old man in the home.

He has been taken into custody and was due to appear in Sutherland Court today.

A crime scene has been established as investigations continue.

While the investigation is in its infancy, it's believed the parties were known to each other.

More to come.