The crime scene in Narara on the Central Coast where a 12-year-old girl was allegedly tied up and sexually assaulted on her way to school.

About 9am the 12-year-old girl disclosed that she had been sexually assaulted by an unknown man while walking to school, according to the Central Coast Advocate.

Police were told the girl was walking along a pathway between Reeves and Carrington streets at 7.45am, when a man grabbed her from behind, took her into nearby bushland, where she was tied up, and sexually and indecently assaulted. The man was dressed in camouflage gear and carrying a hunting knife.

The "brave" girl escaped and made her way to school, where she reported the incident around an hour later. She has since been taken to Gosford Hospital for assessment.

Detectives from the State Crime Command’s Child Abuse Squad and Brisbane Water Local Area Command have launched an investigation into the sickening attack.

A crime scene has been established, and is being examined by specialist forensic officers. Police are also carrying out extensive patrols throughout the area.

Narara Valley High School, where the incident was reported.Source:Supplied

Detectives would like to speak with a man who they believe can assist with their inquiries. He is described as being aged in his mid-20s, 175-180cm tall (5ft8in), with a chubby build, grey/blond hair, and blue eyes.

At the time, he was wearing a knitted camouflage shirt, camouflage pants over navy blue pants, and a camouflage hat, with a loose covering over his face that exposed only his eyes and nose. He was also carrying a camouflage bag.

Members of the public are urged not to approach the man but to contact 000 immediately.

"Thankfully, matters like this are very rare," said NSW Police Superintendent Danny Sullivan. "I’ve got a 12-year-old daughter, I know the feeling of fear that a parent has when this type of matter occurs.

"I know that cold feeling in your stomach.

Anyone with information about the incident should contact Crime Stoppers on 1800 333 000.