Two children, 4 and 12, and woman found dead inside Sydney home in 'very horrific scene'

Two children and a woman have been discovered dead in their own home, with a man arrested and the crime scene described by police as 'very traumatic and horrific'.

Emergency services responded to a 000 call - Australia's emergency number - on Monday (May 18) and arrived at what police have termed a "particularly violent scene" in south-western Sydney just before 8pm.

It was there they discovered the bodies of a 46 year old woman and two children, aged 12 and four, inside the property. Acting Superintendent Michael Moroney told Nine News' morning programme Today that police understand "the deceased and the two children were related" to the 47 year old man charged over their deaths.

He described the crime scene as "a very traumatic scene, a very horrific scene" to journalists, and confirmed that Md Shomon-Ahamed, 47, was detained at a property in Campbelltown where the bodies were found.

He was discovered inside the same residence as the bodies, which bore lacerations and other substantial injuries. Acting Superintendent Michael Moroney said the alleged offence was 'particularly violent' in nature, but refused to divulge details about any weapons reportedly seized from the property, stating only that investigators had recovered "a number of items" inside but confirmed no firearms were involved.

Moroney told reporters on Monday evening that Shomon-Ahamed had no prior police record and detectives were not searching for any outstanding suspects.

While there was no immediate suggestion that mental health issues had played a part, he said that would be examined as part of the continuing investigation.

A substantial police presence remained at the suburban Sydney street well into the evening as officers maintained a crime scene around the cordoned-off property. Police tape encircled the home while marked vehicles lined the road, with officers seen working in the front garden, according to Nine News.

The investigation is being conducted by Campbelltown detectives with assistance from the State Crime Command's homicide squad, as police appealed for anyone with information to come forward.

The harrowing discovery was made just hours after NSW Police announced that hundreds of arrests had been carried out during a statewide crackdown targeting repeat domestic violence offenders.

"This today appears to be not something that we had on our radar in terms of being known to police," Moroney said. "But I can reassure the public that domestic violence is the number one priority for NSW Police, and we will continue to target DV offenders."