The man taking the Department of Corrections to the Waitangi Tribunal for failing Maori is confident he has a strong case.

LISTEN: Former probation officer Tom Hemopo talks to Newstalk ZB about his claim to the Waitangi Tribunal about the Department of Correction's alleged failure to address Maori reoffending.

MORE: Tom Hemopo's lawyer Roimata Smail spoke with Larry Williams.

Former probation officer Tom Hemopo is seeking an urgent hearing, after the department scrapped its plan for reducing Maori reoffending.

He said Maori continue to be over-represented in prisons, and Corrections isn't meeting its treaty obligations.

"I think this one is very strong. There is a lot of things there that need to be fixed."

The claim is the latest challenge for the embattled Department of Corrections.

Mr Hemopo said Corrections need to recognise Maori imprisonment rate and reoffending rate can be reduced, and the department needs to do its part.

"It's about stereotyping that Maori are inherently criminal."

Mr Hemopo is taking the case on behalf of Ngati Maniapoto, Rongomaiwahine and Ngati Kahungunu.

However, he said reduced reoffending will benefit the whole country and he has invited other iwi to be involved.

Maori make up about 16 percent of the population, but about 51-percent of the prison population.

Corrections prepared a report into reducing Maori reoffending in 2012.

It found a kaupapa Maori approach (by Maori for Maori) and the involvement of whanau were critical in reducing Maori offending.