A four-year-old boy is dead and his mother has been charged with murder after police responded to an "extremely confronting scene" at a unit at Wyong on Saturday.
Police said a 32-year-old woman went to Wyong police station about 4.40pm on Saturday, triggering a concern for welfare.
Police have said officers tried to speak to the woman but were unable to do so.
Tuggerah Lakes police went to a unit in Wyong and found the body of a four-year-old boy.
Police said the boy had suffered "significant arm injuries" and Tuggerah Lakes Superintendent Chad Gillies told reporters on Sunday morning that police were confronted with an "extremely confronting scene".
Police established a crime scene and the woman, who was still at Wyong police station, was arrested.
She was later charged with domestic violence murder and did not appear in a bail divison court or apply for bail on Sunday.
Judge Les Brennan adjourned the matter to Wyong Local Court on September 1.
Tuggerah Lakes detectives and the NSW Homicide Squad are investigating what led up to the child's death and police were expected to remain on scene throughout Sunday.
Police also seized a vehicle for forensic examination, which is believed to be the car the woman used to drive to the police station.
Superintendent Gillies said the boy was found alone in the home and it was not believed at this stage that there was anyone else involved.
He said the crime scene was still active and while police had seized a number of items he would not be drawn on whether police had found a weapon.
Superintendent Gillies said the boy had suffered injuries, but police would wait for an autopsy to determine the time and cause of death.
He said the 32-year-old woman was known to police, but would not comment on whether she had a history of domestic violence.
"Whenever a child is a victim of violent crime and whenever a child is murdered, it strikes at the core of the community," Superintendent Gillies said.
"That's why it's absolutely important we work through this methodically, we try to understand what's happened, why it's happened.
"And from my perspective, we owe that to that little boy to make sure that we get the exact circumstances and present them to the court in due course.
"And that is the focus over the coming days and weeks for investigators."
Police said if anyone had any information about what happened inside the unit or in the days prior to contact Crime Stoppers on 1800 333 000.
1800 RESPECT (1800 737 732)
Lifeline 13 11 14
Men's Referral Service 1300 766 491
