Stabbed teen begged for help on Sydney doorstep

A 17-year-old boy is in hospital with serious injuries, after he was stabbed in the back and arm in Sydney's south-west last night.

The bleeding boy asked for help from a woman at a home in Kenilworth Street in Miller just before 7.30pm.

"I just heard a scream and a young bloke come running in my front door and just blood was everywhere, he had a stab wound on his back," the woman told 9NEWS.

Police were called and are searching for up to five young people, after his attackers fled the scene.

A dark car was also seen leaving the area, and a pair of scissors could be seen on the ground.

The teen is being treated for non-life-threatening injuries at Liverpool Hospital.

Anyone with information is urged to contact Crime Stoppers on 1800 333 000