The Corrections Department is to spend millions of dollars on treating prisoners for drug and alcohol addiction after they have been released.
Corrections Minister Sam Lotu-Iiga announced $8.6 million spending over the next three years this week, saying breaking prisoners' addiction will help them reduce reoffending rates.
Two-thirds of prisoners have substance abuse problems and more than half of crimes were committed by people taking drugs and alcohol, Mr Lotu-Iiga said.
"There is a range of drug and alcohol treatment programmes available inside prison. However, there is limited post-release support to maintain the life changes prisoners make.
"It is important they keep the motivation to stay free from substance abuse once they leave prison."
The government's goal is to reducing reoffending by 25 per cent by 2017.
"Breaking the link between substance abuse and offending is crucial if we want to reduce the number of people in prison," Mr Lotu-Iiga said.