The girl was walking to school along a path at Narara, on the Central Coast, about 7.45am when she was grabbed from behind and dragged into nearby bushland.

A man wearing camouflage clothing and wielding a hunting knife tied her up before she was sexually and indecently assaulted.

Police say the girl was eventually able to escape, running to school where she raised the alarm at 9am.

She was taken to Gosford Hospital, where she remained on Monday evening.

Police immediately began to investigate the incident, using police tape to cordon off a crime scene between Carrington Street and Reeve Street in Narara.

Specialist detectives from the Child Abuse Squad are involved in the investigation and detectives and uniformed police are expected to take to the streets in Narara on Tuesday to seek out potential witnesses.

Superintendent Danny Sullivan, from Brisbane Water Local Area Command, said the girl was on a common thoroughfare regularly used by students and dog-walkers when she was grabbed.

He said the girl was understandably distressed, but was working closely with police and hospital staff.

"She was able to give us a very clear description of the alleged offender," Superintendent Sullivan said.

The man is described as being in his mid-20s, 175cm to 180cm tall, with a chubby build, grey/blond hair and blue eyes.

At the time of the attack 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 his eyes and nose.

Police said he was also carrying a camouflage bag and is in possession of a hunting knife. Anyone who sees a man matching this description is urged to contact triple-0 immediately.

Superintendent Sullivan said police were working closely with the Department of Education to warn other students in the area.

He said the path where the girl was grabbed was used by many residents, including those travelling between their homes and public transport stops, so people may have information who have not spoken to police.

Police have asked anyone who may have seen something - even if they think it trivial - to come forward.

Detectives will man a command post at Narara on Tuesday so members of the community can speak to officers face-to-face.

Superintendent Sullivan said there was "rightly" community outrage about the attack.

"My daughter is the same age, and I know that feeling a parent feels when they hear a story like this," he said.

"That's why we're working methodically and closely with our State Crime Command and doing all avenues of investigation."

Those with information are asked to call Crime Stoppers on 1800 333 000.

smh.com.au