Labour has come up with a radical solution to the high number of Māori in jail - it wants a separate Māori prison.

It wants to convert an existing prison into one run entirely on Māori values.

"A prison based on Māori values, not exclusively for Māori but for anybody, but they'll know that the values that the prison will be run under will be based along Māori lines," Labour's Corrections spokesperson Kelvin Davis told Newshub.

There are 10052 prisoners and 5077 of them are Māori, making up 50.5 percent of the prison population.

Mr Davis says if Labour wins, he wants to make one of New Zealand's 18 prisons a prison for Māori, run by Māori on Māori values.

"Why don't we just try, have the courage to try one of those 18 prisons and run it along kaupapa Māori lines," he said.

Former inmate Joseph Tawa, who has spent 10 years in prison, says it could work.

"In a way I think it may reduce the amount of reoffending, because of getting to know your whakapapa and your tikanga, which is very important to us as Māori people," he told Newshub.

It's a major turnaround by Labour which just seven years ago, said it was against Māori prisons.

Mr Davis wants to convert Northland's Ngawha prison into the Māori prison, saying it would be an "excellent place".

And while it would be a Māori prison, other ethnicities would be allowed.

"Even if there are some people that are just going to pooh-pooh it, well, to hell with them," Mr Davis said.

The proposed Māori-only prison is a really big call from a major party like Labour - there will be plenty of critics who call it race-based justice.

It's a big call in order to deal with a big problem.

Newshub.