Police are hunting a man who car-jacked a Christchurch teenager in broad daylight at the weekend as he tried to find a car park at a busy sports venue.

The teen drove to Cowles Stadium on Saturday afternoon to play sport.

While he was looking for a car park, he saw a teenager he had previously attended school with.

The teen, who lives out of Christchurch city, had not seen the girl for some time and the sighting was a total coincidence as she has no connection to his sport.

His stepmother told the Herald that the teen opened his car window to speak to her and said she "started screaming" at him.

Then a man wearing a ski mask jumped out of her car and into the 16-year-old's.

"He got in the passenger seat and forced him to drive around some streets in Aranui," said the stepmother, who cannot be named to protect the teen's identity.

"He demanded money off him but he didn't have any, then he forced him out of the car and took off in the car.

"It was really terrifying… it happened in the middle of the day and that car park was packed, it could have been anyone."

The woman said the incident was reported to police and an officer took a statement from her son.

The teen's car was found later that weekend and the 16-year-old's father called the police to let them know.

But the family were disappointed that officers did not go and retrieve the vehicle.

"His dad asked if they wanted to fingerprint it but they were not interested… they said 'no you can just go and tow the car away'," the stepmother said.

"This has been a violent incident… the guy wasn't wearing gloves… don't you think it would be a good idea to get some forensics or something?

"But no, they were not interested - whether it's because he's only 16 or because it happened in the middle of Aranui or my son had no insurance I don't know.

"It doesn't matter though, this was bloody terrifying and it happened in a busy car park in the middle of the day - it's not like my son has gone to meet up with people to give them drug money or something.

"And obviously my son is terrified this guy will come back next week…"

A police spokeswoman said inquiries were ongoing.

"Police are continuing to investigate this matter and are committed to identifying and holding the person involved to account.

"We acknowledge this would have been a very frightening incident for the teenager and his family."

She said since the incident police had spoken to the victim and his father.

There had been "some confusion" around the towing of the car and police would make "further inquiries" into that matter.

However, they were endeavouring to take any evidence they could from the stolen vehicle.

"We have contacted our forensic teams to see if they are still able to forensically test the vehicle," said the spokeswoman.

"We have other inquiries to make which include checking for CCTV."