A 14-year-old boy accused of stabbing a student at the University of Sydney has faced charges that were dismissed by a court, a state government minister has said.

Newspapers have also reported that the boy was accused of threatening to shoot fellow students.

The boy is the third Australian child to be accused of a stabbing attack linked to online radicalisation since April, prompting authorities to warn parents to beware of internet dangers.

The boy remained at a Sydney hospital for a mental health assessment the day after the early Tuesday attack, New South Wales Police Minister Yasmin Catley said.

Ms Catley said: “We have to make sure that we wrap services and support around these kids who are being radicalized online and their families.”

Police say the boy took a bus from the site of the stabbing to the hospital seeking treatment for a cut on his hand. He was arrested at the hospital.

The 22-year-old student who was stabbed once in the neck was discharged from the same hospital overnight, Ms Catley said.

The boy wore military clothing and used a kitchen knife in the attack, police allege.

Ms Catley said the suspect was charged by police last year and a court dismissed the charges. She added that he had been attending a Department of Communities and Justice programme, which news media have described as a deradicalisation program.

Sydney’s The Daily Telegraph newspaper reported that the suspect was charged last year with threatening to shoot fellow students at his Sydney school and with threatening to engage in self-harm, but a magistrate dismissed the charges in February on mental health grounds.

Police have yet to determine a motive or file charges.

A 16-year-old boy was shot dead by police after he stabbed a stranger in a hardware store parking lot in the Australian city of Perth on May 4. The victim survived.

That teenager had also been taking part in a deradicalisation program since he detonated a homemade explosive device in a school washroom two years previously.