The Council of Trade Unions (CTU) has called on the Maori Party to drop its support for privately managed prisons.
It is government policy to allow the private sector to tender for prison management and yesterday a bill was introduced to Parliament which will allow that to happen.
The Maori Party has said private management would open opportunities for Maori to become involved in running prisons and work with Maori inmates.
CTU vice-president Maori, Sharon Clair, said today privately managed prisons were not interested in anything except the continued imprisonment of people.
"Maori are over-represented in the prison population and the Maori Party should focus its efforts on reversing that, rather than advocating that the state, having imprisoned our people, then delegate responsibility for looking after them," she said.
Prime Minister John Key said on Monday that most prisons would continue to be run by the Corrections Department but it was "eminently possible" that some would by run by private contractors.
The Corrections (Contract Management of Prisons) Amendment Bill says it is government policy to allow competitive tendering of prison management on a case-by-case basis.
"Opening up prison management to contractors provides an opportunity for innovation and change in the way in which prisons in New Zealand are operated," it says.
"Providing for prisons to be run effectively and efficiently by contract managers also enables the Government to look for cost savings in the overall delivery of prison services."
The bill noted that Auckland Central Remand Prison (ARCP) was managed under contract from 2000 to 2005.
"During that time ARCP made a number of improvements that were subsequently adopted by the Department of Corrections."
Labour and the Greens strongly oppose privately run prisons and say locking people up is the responsibility of the state.
The previous Labour government refused to renew the ARCP contract.
