Prisons are at the sharp end of the state's power. Right now, the corrections system is the site for a renewed fight over privatisation.

The catalyst is the Corrections Amendment Bill, soon to come before Parliament, which is aimed at tidying up corrections law and includes a clause abolishing private contracts to manage prisons.

Currently the Auckland Central Remand Prison (ARCP) is New Zealand's only private jail. It was built with public money and then had its management contracted out by the previous National Government. With all the right-wing parties supporting privatisation, the legislation needs the Greens' support to be passed.

The state’s coercive power is at its most extreme in a prison. Guards have very serious control over the lives of inmates. With 'reasonable' force, but with relatively little justification, they can inspect orifices and generally humiliate other human beings. The only other comparable group in society is the police and most people wouldn't allow Securitas to run the constabulary, even if they were cheaper or more efficient.

How can the free market be the solution to the problems of a prison system? The key to a successful business is repeat customers - a perverse incentive.

So the issue of private prisons is quite different from the commercial provision of health or other kinds of social services. It is more complex than simply saying "private good, public bad" or even, "the private management of ARCP works, so leave as it is".

So who is behind ARCP and why is it 'successful'?

Australasian Correctional Management (ACM), which runs the facility, is a subsidiary of GEO Group. In 2000, in its former incarnation as Wackenhut Corrections, GEO received a placing in the (UK) Observer's "Golden Vulture" awards for, among other things, "sadism, greed and frightening incompetence" and has been subject to allegations of sexual abuse, physical violence and unsafe work practises.

The Australian Medical Association and others have called for an independent inquiry into ACM's immigration detention centres in Australia, based on staffing problems, substandard services and child abuse.

The problems are not confined to the detention centres. At least one court case has found ACM guilty of unsafe work practises in their prisons, and there is continuing concern in Australia that those problems have not been adequately addressed.

The Auckland remand prison is ACM's glossy New Zealand sales brochure, so the company is on its best behaviour until it has consolidated its position. This is all about market share.

For politicians committed to the privatisation agenda, ARCP keeps the door ajar to private prisons.

All this is no criticism of the recently resigned General Manager at ACRP, Dom Karauria. In fact it is primarily due to his excellent work that this remand prison has satisfied its community stakeholders.

The fact that ARCP is privately operated is not intrinsic to its success, which is clear from the problems that dogged it before Dom was appointed. It is also a brand new facility, and, being a remand prison, is without the same pressures and obligations found in the main penal system.

Under Dom's leadership, ARCP has been congratulated on its relationship with tangata whenua. But that relationship was first developed by the department and the requirement to work with local iwi was a provision of the contract with government. ACM has no inherent interest in the Treaty relationship.

Although cost should not be a measure of success in corrections, claims have also been made by some MPs that the 'per head' cost of imprisonment is less at ARCP than in the public system. But this is an 'apples and oranges' comparison because the government has met the infrastructural costs of ARCP such as the building and I.O.M computer systems. The public service is cheaper when a proper comparison is made.

In any case, whether the new corrections legislation is passed or not, the Labour-led government will not renew the ACRP contract when it ends next year.

Our prisons are not effective at rehabilitation and the Greens do not defend the status quo within the public system. Disturbingly, with new 'tougher sentencing' laws in place, the government has boasted in Parliament that the prison population will soon increase by 20 per cent.

But the challenge for the Green Party is to negotiate corrections legislation that will improve the prison system and to promote policies that will lead to a more inclusive and just society that makes prisons redundant.