The Irish Prison Service said more people are being sent to prison and overcrowding has once again become an issue in Irish prisons.
The number of inmates has increased by 11% in the last two years, with more than 4,000 people now in custody on a regular basis.
Remand prisoners have increased by more than a quarter, are in custody longer and face more serious charges.
Many require higher levels of security because of the nature of their offences and their links with criminal gangs.
There has also been an increase of 59% in the number of women being sent to prison.
The Prison Service also said the prison population is getting older with the number of inmates over-50 doubling in the past ten years, some with complex needs, including specialised healthcare.
There has also been an increase in the number of sex offenders being sent to prison and this is expected to increase further over the next three years.
Overcrowding is again a reality in the prison system, with just 133 spaces for 179 female inmates on 31 March this year.
On the same day, there were 741 remand prisoners in custody and with just 431 spaces in Cloverhill Remand Prison, the inmates had to be spread out across the system.
There is also evidence of an increase in the number of people committed to prison with severe and enduring mental illnesses, which the Prison Service said presents challenges in providing appropriate access to mental health services and facilities.
The Director General of the Prison Service said it plans to further develop the integration of prisoner care and deliver more effective rehabilitation to inmates over the next three years.
Caron McCaffrey also said it plans to invest in a prison estate that provides safe, secure and humane custody, to create a more supporting, working environment for staff and ensure an open, transparent and accountable Prison Service.
The Irish Penal Reform Trust has welcomed the Director General's commitments, but said the Prison Service will not be able to achieve its strategic goals unless prisoner numbers are reduced and overcrowding addressed.
IPRT Executive Director Fíona Ní Chinnéide also said Ireland continues to be over-reliant on prison and people with mental health issues must be diverted to more appropriate settings.