A teenager's six-day joyriding spree around Christchurch in other people's cars has brought him a seven-month jail term despite his promise to the judge to "be good".

Dennis Tunnicliffe was 18 when he and an associate took nine vehicles, almost all Subarus, from September 28 to October 3, attempted to take another and unlawfully interfered with another car.

He admitted all the charges as well as a breach of bail, and after spending three and a half months in custody on remand he appeared for sentence before Judge Noel Walsh in the Christchurch District Court today.

Defence counsel David Bunce said he hoped that the sentence could be kept short so that Tunnicliffe would have already served most of it, and that was granted.

The seven-month term will mean immediate release under the prison's system of half-remission.

Bunce said home detention was not practical because of the time Tunnicliffe had served, and because although he had family support, he would be sleeping on a couch in a sleepout.

Child, Youth and Family was not keen on the overcrowding that would result.

Judge Walsh was not keen because it would be a recipe for failure.

"No doubt your dodgy mates would soon be knocking on your door," he told Tunnicliffe.

Bunce said the offending arose from the people Tunnicliffe was associating with and his difficulties with alcohol, and he suffered from anxiety and depression.

Judge Walsh told the unemployed youth: "You have caused misery and distress to a number of victims, as well as financial loss."

He noted previous convictions for receiving, theft, burglary, possession of a firearm and being an unlicensed driver.

Some of the latest offending took place while Tunnicliffe was doing a sentence of community work.

Tunnicliffe wrote to the judge, saying he had learnt his lesson and had not enjoyed being in jail and away from his family.

He wrote: "I never thought I would come to jail. I apologise to the people whose cars I damaged. If I get home, I'll be good, Your Honour. I want a chance to prove myself."

Judge Walsh told him: "Your future is entirely in your hands. Unless you want to waste the best years of your life sitting behind steel bars and concrete walls with dodgy cellmates, you know what's got to happen - you have got to make changes."

He sentenced Tunnicliffe to jail terms totalling seven months, with six months of release conditions to attend counselling and treatment for alcohol, drugs and offending issues.

He also ordered him to make reparation payments of $9550 for the damage he did.

- © Fairfax NZ News