Prisoners are finding it harder to get work experience and are more likely to be recalled for breaching parole.
Justice campaigners say work experience is vital if prisoners are to successfully reintegrate into society.
Figures from the Corrections Department show that the number of prisoners convicted of breaching their parole has doubled since mid-2007, while the number on work release programmes has dropped by almost a quarter.
Groups which work with prisoners, such as the Howard League for Penal Reform and the Salvation Army, say work experience is vital if prisoners are to successfully reintegrate into society.
They say the changes are a reflection of a more risk-averse attitude adopted since a man was killed near Lower Hutt in 2007 by a murderer on parole.
The department says its job is to ensure public safety.