The man thought to be New Zealand's worst drink-driver has applied for leave to appeal against a jail sentence he has already served, so he can get drug and alcohol treatment.

Brian Mitchell Hart, 58, from Hawkes Bay has applied for leave to appeal his 33rd prison sentence for his 20th drink-driving conviction.

Hart's lawyer John Dean told the Court of Appeal in Auckland that Hart wanted to serve a community sentence at an alcohol rehabilitation clinic.

Hart was sentenced to 12 months in prison in February on two drink-driving charges, and was expected to be released from prison tomorrow.


Mr Dean told the Court of Appeal that Hart's brain was "addled since drinking since he was 16" and he suffered from dementia.

"He's a loner ... he has spent more than half his adult life in jail."

He said Hart had never received treatment for his alcohol addiction while in prison.

Crown prosecutor Kylie Cooper said the Crown understood that this was the case, however she said Hart had been offered treatment but refused to participate.

Justice Lynton Stevens, Justice Simon France and Justice Jillian Mallon questioned the admissibility of an affidavit submitted by the defence from alcohol and drug counsellor Roger Brooking.

Mr Brooking interviewed Hart in February and found he had alcohol-related dementia. Mr Brooking said in his affidavit that Hart would need to attend a long-term residential rehabilitation centre to address the alcohol dependency.

Justice Stevens said imposing a new sentence on Hart after he had already served an initial sentence could be a risk of "double jeopardy".

The decision has been reserved.