Warning: graphic content.

Shocking new allegations have emerged after a mother allegedly murdered her four-year-old son.

The 32-year-old woman entered Wyong Police Station, on the NSW Central Coast, and made statements that concerned officers about 4.40pm on Saturday.

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Her son’s badly injured body was found at a nearby home shortly after by officers conducting a welfare check.

Police believe he had been “deceased for some time” before his body was found.

The woman, who can not be named for legal reasons, allegedly cut off and cooked parts of the boy’s arm before turning herself in.

Police are now investigating whether cannibalism was involved.

A court granted investigators the power to carry out a DNA test on the mother’s mouth and collect a sample of blood and a nail clipping.

She was charged with murder and had bail formally refused during an appearance before the Bail Division Court on Sunday.

A 32-year-old woman is accused of killing her four-year-old son in Wyong, NSW. Credit: 7NEWS

Heartbroken locals have laid flowers at a growing tribute to the young boy. Credit: George Chan/AAP

Scrutiny over child protection

The Department of Community and Justice on Monday revealed that child protection workers had visited the family three times during the boy’s short life.

NSW Families and Communities Minister Kate Washington refused to comment on claims the 32-year-old had drug-induced psychosis.

“There are many complexities involved in this case and I do not want to prejudice the criminal investigation that’s underway,” she said.

Washington denies her department is losing control despite thousands of cases slipping through the cracks, with shadow minister Natasha Maclaren-Jones claiming close to 150,000 young people who had reports presented not seen by a caseworker.

The independent review will investigate how department workers acted and why, given the history, the child was living with the mother and whether more could have been done.

“I intend to publicly release the review subject to any legal constraints,” Washington said.