Planned changes to prison inspection reporting will not make jails safer, the Green Party says.
Corrections Minister Judith Collins has ordered her department to give her regular updates about prison inspections and to publish more reports in response to an inquiry into fight clubs at Mt Eden Prison in October.
Mrs Collins said prison inspectors may also be given greater powers.
However Green Party justice spokesperson David Clendon said the inspectorate needed to be made fully independent rather than just have the minister looking over its shoulder.
"I fear this new mechanism the minister's proposing could actually have a perverse outcome, that the people reporting are actually making themselves vulnerable by admitting that things are going badly.
"So I strongly believe that we should cut directly to an independent agency."
Mr Clendon said the minister should already have been exercising better oversight, and that the latest moves may be used as an excuse not to set up an independent inspectorate like many other countries have done.