New South Wales police investigating whether a 14-year-old boy who allegedly stabbed a 22-year-old student at the University of Sydney has extremist links believe he may have been influenced by a “salad bar” of mixed ideologies.

Australian police said it had arrested a 14-year-old boy after a stabbing at the University of Sydney on Tuesday morning, which triggered a lockdown of the university buildings.

The 22-year-old was taken to hospital in a serious but stable condition after the teenager allegedly stabbed him in the neck with a kitchen knife at the university campus in Sydney’s inner west after 8am on Tuesday.

The boy, who was dressed in a camouflage military uniform, allegedly fled the scene on foot before a member of the public helped him catch a bus to hospital, where he was arrested, treated for cuts to his hand, and underwent a mental health assessment.

The NSW police counterterrorism and special tactics command is investigating the incident in partnership with the Australian federal police, although they had not declared it a terrorism incident as of Tuesday afternoon.

Police were investigating potential extremist links, including white supremacy, but they had not identified a specific ideology, which is required before an incident can be designated as a terrorist act.

New South Wales Police Assistant Commissioner of counter terrorism Mark Walton told a news conference the boy's motive or ideology had not yet been determined, but expressed concern at increasing evidence young people were being radicalised online.