The Department of Corrections will be under greater scrutiny to ensure that no prisoners are being tortured, a prominent Auckland criminal lawyer says.

The Office of the Ombudsman will be stepping up its monitoring of Mount Eden prison after an investigation found private company Serco was negligent in its running of the facility.

A report released on Thursday detailed lax supervision, regular organised fights and some prisoners being denied proper medical checks and access to lawyers.

The Ombudsman will be carrying out regular inspections and unannounced visits to prisons.

Auckland lawyer Tony Beach said the Ombudsman will be checking to see if the Corrections Department is complying with the Crimes of Torture Act, "to ensure that there is no torture or ill treatment of those who are in detention."

The Act is meant to fulfil New Zealand’s responsibilities under the United Nations' Convention Against Torture.

Beach said New Zealand doesn't want to be seen as a place that allows ill-treatment of people in the custody of the state.

"It's something that would reflect badly on New Zealand internationally," he said.

Among the findings, the report from the Chief Inspector of Corrections says in June and July last year organised fights were regular affairs, likely to be happening at least once a week.

"Prisoners reported that if they refused to participate they would be threatened, "pack attacked" or assaulted by (gang) senior members," it said.

Guards were at times found to be playing pool or table tennis instead of supervising inmates and some prison areas went more than two hours without being watched due to staffing shortages.

Corrections has made 21 recommendations, calling for a raft of changes to staffing and procedures at the prison.