I do agree with this and I do think that companies should audit federal prisons on a regular basis. Both private and federal. Private companies should not be sponsored. Just because those who are incarcerated have done wrong things does not mean they deserve barbaric actions on them done by part of the system of federal prisons.
Just like state-run prisons, private prisons are likely to be hotbeds for abuse and human rights violations. Private prisons are even more susceptible if they aren't adequately monitored and have no one to answer to other than a board of directors. Private prisons should be avoided, but they certainly should be investigated when violations are alleged.
Just because someone's behavior has proven to be criminal does not mean that individual has lost all their rights as a human being. Any correctional facility, whether operated by the government or private industry, should be held up to the same standard of care for its inmates. They are still people, no matter what crimes they may have commited.
Yes, private prison companies should be investigated for abuse. These companies may neglect providing prisoners with proper care in order to save money. This applies not only to the country of New Zealand but also any other countries that have private prisons. Prisons should not be allowed to neglect or abuse the inmates.