The number of women in prison since 1986 has grown at nearly twice the rate of men according to the Department of Corrections Offender Volumes Report 2009, released today.

The report, which presents information about the offender population managed by Corrections in prisons and in the community, shows that between 1986 and 2009 the number of female sentenced prisoners increased from 98 to 389 - a growth of 297%. Male sentenced prisoners increased from 2,359 to 6,157 - a growth of 161% over the same period.

Corrections Manager Strategy and Research, Dr Peter Johnston, said the report includes a summary of trends in the Department's workload and trends in the known offender population of New Zealand since 1980.

"The report helps Corrections to plan and develop robust policies. It demonstrates the impacts of past and recent justice sector policies on the offender population managed by Corrections. It also helps Corrections to decide which offender groups it needs to target its rehabilitation activities at.

Dr Johnston said the report, which analyses offenders by age, gender, ethnicity, offence type, sentence type and sentence length, plus a range of other variables, contained a wealth of interesting information, this included:

The number of sentenced youth prisoners had decreased over the past 25 years. In 1986, there were typically 500 sentenced prisoners aged 15-19 years, in 2009 there were typically 400;

The growth in the number of sentenced prisoners has been largely driven from the growth in older (30 years plus) offenders. In 1980 prisoners aged over 30 were 20% of the sentenced population - this had increase to over 60% now;

Longer proven offending careers of prisoners. In 1980 almost 75% of sentenced prisoners had recorded their first conviction within the previous 10 years. In 2009, less than 38% had recorded their first conviction within the previous ten years;

Growth in the percentage of offenders serving prison sentence for violent, sexual and drug-related offending;

Though the numbers of sexual offenders being sent to prison had been relatively constant since 1993 there has been a trend towards sex offenders being in prison for longer periods; and

There were twice as many Maori 25 year old males in prison than there were European males of the same age. 3% of all Maori men aged 25 years old are in prison.

Dr Johnston said the report also included useful information for the Department on the growth in the number of offenders on community sentences.

"The number of offenders managed at any given point in time on community sentences by Community Probation & Psychological Services has grown nearly 80% over the past three years. In 2006 CPPS managed 18,000 offenders, by 2009 it had grown to around 32,000.

"Much of this growth had been for offenders aged 20-29, in 2006 there approximately 8,000 offenders in this age group on community sentences, in 2009 this had increased to 14,000."