Christchurch police are appealing for witnesses after an alleged abduction attempt on a young boy.

It's believed a man approached and persuaded a nine-year-old boy to get in his car on Bower Avenue in New Brighton around 3.45 yesterday.

After a short altercation the boy escaped the car and and scooted home - he was left with a scratch on his leg.

The man is described as a 28-year-old Caucasian with a brown beard, wearing a black polo shirt and green pants.

His car is a new shape four-door sky blue Suzuki, possibly a Swift.

Police are urging anyone who saw the incident or the car to contact them urgently.