A 12-YEAR-OLD boy screamed for help as he watched three teenagers stab his father with a broken bottle, supposedly for refusing to let them have a ride on the boy's bike.

Wei Kuo Chao, 58, had taken his 12-year-old son to Endeavour Park in Canley Vale on Saturday evening when they were approached by three youths, one of whom was carrying a broken bottle. The teenagers asked to have a ride on the boy's bike but Mr Chao refused and told his son to quickly ride home, a police spokesman said.

Mr Chao was then chased by the teenagers and stabbed in the elbow and back in a front yard on Prince Street, just metres from his home. Neighbours heard the boy scream for help, saying the boys were trying to kill his father.

The three teenagers, described as being of Mediterranean or Middle Eastern appearance and about 15 years old, then ran from the scene. Mr Chao managed to run home and was taken to Liverpool Hospital because he was bleeding profusely from the arm. He remains in a stable condition.

Cabramatta police are appealing for witnesses.