An Australian woman has been charged with murder after allegedly decapitating her mother in front of a child.

Police have not confirmed the nature of the death but news reports in Sydney said the victim was beheaded.

New South Wales Police Detective Superintendent Brett McFadden described the attack as "up there with one of the most significant, most horrific scenes police have to deal with" – adding that the injuries to the victim "were extensive."

Police believe an argument between the woman and her mother became violent.

Neighbours reported the incident and when police arrived at the scene, the mother’s body was found in the home, with multiple injuries.

The daughter was arrested outside the home of a neighbour and a four-year-old boy was taken to hospital with what police said was a minor head injury.

He has since been released.

The daughter has appeared in court and been referred for a medical assessment.

She told the court that she suffered from mental illness and other medical conditions, adding: "I couldn't even wash myself properly when I had to shower to get all the blood off."

Detective Superintendent McFadden said officers who investigated the scene have been offered counselling.

"The detectives are now working meticulously through the information available to us, but it's a very difficult and challenging investigation.

"It is also in its very early stages and as you'd understand there is still a long way to go in this inquiry."

The Australian Broadcasting Corporation quoted him as saying: "We understand at this stage that a number of knives were used during the course of the incident.”

Information supplied by Met Éireann