Investigators have released a photo of a man being sought over the attempted abduction of a 13-year-old girl who was dragged off her bicycle into bush near Timaru.

Police have named Washdyke man Blaine Ross Hughes, 20, as a person of interest and say he is is believed to have information that may help with their inquiries.

The alleged abduction attempt on Tuesday in Washdyke, near Timaru, was stopped by a nearby resident who saw the attack and went to the girl's aid.

Detective Senior Sergeant Marion Neill said Hughes may be driving a green Isuzu Bighorn, registration YA9089, which was reported stolen yesterday from a Washdyke address.

"This man may still be in the South Canterbury area, but he is also known to have associates in Christchurch and other parts of the South Island,'' she said.

"We are appealing for him to contact us, or for anyone who knows his whereabouts to pass that information on to police.''

Police have described the alleged offender as a solidly built Caucasian, aged in his 20s, about 1.7m tall. He was clean-shaven with dark hair and dark complexion.

The man was reported to be wearing a cap, a white hoodie with a grey triangular pattern and maroon jeans.

Timaru police said they were continuing to appeal for information from anyone who was around Sir Basil Arthur Park between 7.45pm and 8.20pm on Tuesday, or who had information about the incident.

The girl had been riding her bike on State Highway 8 near the park when she was allegedly approached by the man.

A short time later he dragged her off her bike, across a fence and into an area of bush, Ms Neill said.

A witness from a nearby property went to help her and the assailant ran away. A police dog team was unable to find him.

- APNZ