Another critical report has surfaced about the operations in the UK of prison operator Serco.
Serco is New Zealand's only private prison operator and runs Auckland's Mt Eden jail.
Britain's Independent Monitoring Board has identified what it calls clinically unsound health practices at Norwich Prison.
The board says medication is not dispensed to inmates in a consistent way, meaning that prisoners can be without vital medication for an unacceptable length of time.
The report also says prisoners don't always receive the correct dosage or even the correct medication.
Serco was last year faulted for its role in the death of a 14-year-old at its youth jail in County Durham and for having the poorest record of self-harm in Scottish jails.
In a statement, Serco UK Clinical Healthcare managing director Paul Forden says it agrees there were aspects of its service last year which needed improvement, and it is now working with the prison as well as health services in Norfolk.
He says changes have been made including ending arrangements which subcontracted aspects of the service to another organisation and bringing in new managers.