Search for Sydney teen stabber, accomplice

A manhunt is underway after a teenage boy was stabbed in an unprovoked attack outside a Sydney shopping centre.

The 16-year-old local boy had been buying groceries at Woolworths in Balmain with his brother and a teenage friend on Thursday evening when they were confronted by a man in the supermarket's rear car park.

The man asked the teens for a lighter in a "one-way conversation" before stabbing the teenager in the abdomen and hand, Acting Superintendent Anthony Bell said.

Police have described the attack as "swift and unprovoked".

The attacker fled on foot, along with a female associate, before paramedics arrived.

Riot police and forensic dogs spent Thursday night and Friday conducting extensive searches of the area but have been unable to find the attacker.

Supt Bell called on any members of the public who were in the area around 6.40pm or shortly after, particularly anyone with dashcam footage, to come forward.

The man is described as Caucasian with ginger hair, Australian accent, 185-190cm tall, of solid build and aged in his late 20s to early 30s.

There is no description of his female accomplice but Supt Bell urged her to turn herself in.

The boy was taken to Royal Prince Alfred Hospital, where he underwent emergency surgery. He had another operation on Friday afternoon.