Justice sector groups have criticised National's policy of allowing private management of prisons, but say there are good ideas in many aspects of prisons policy.
Beven Hanlon from the Corrections Association, the union that represents prison staff, said privatisation means the companies running prisons would cut corners to make money.
He said that would mean fewer staff, who would also be lower paid, would be available to deal with violence in prisons. He believes rehabilitation programmes may also be cut.
National's Corrections spokesperson, Simon Power, told Morning Report when Auckland Central Remand Prison was in private hands, many improvements were made which Corrections subsequently adopted when it took over the prison.
He said they included better education programmes, more staff dedicated to behavioural assessments, physical training, sentence planning and crime prevention.
Howard League for Penal Reform president Peter Williams QC described the policy as refreshing and containing a lot of good ideology, but said there may be pragmatic difficulties in implementing some of the ideas given the bleak economic outlook.
However he said the league opposes private prisons because of the difficulty of holding providers accountable.
National is also pledging to boost the number of prisoners carrying out work by the year 2011, and double the number able to receive drug and alcohol treatment.
It would also deny parole to prisoners who refuse to take part in work schemes, an idea that Sensible Sentencing Trust spokesman Garth McVicar says its a good one, and restores parole as a privilege.
Rethinking Crime and Punishment director Kim Workman said education programmes in prisons may not reduce re-offending, but do improve rehabilitation of prisoners.
He said neither Labour nor National have a comprehensive prisoner reintegration strategy, and is pleased National has pledged to have a look at such a strategy.