The Irish Prison Service has confirmed that prisons have reached capacity and are now overcrowded, following a temporary dip during the Covid-19 pandemic.
As of Friday, 167 prisoners were sleeping on mattresses on the floor, with half of them in Dublin's Mountjoy Prison.
One prisoner, who had just been released from Mountjoy last Thursday, said it was overcrowded.
"It's packed in there. It's all double cells and all that, the place is wrecked …it's against your hygiene," he said.
One couple, visiting their grandson, said they were told that in some cases there's currently three to a cell in Mountjoy.
"Most of them are two to a cell, but there’s only supposed to be one prisoner in each cell. Some are three in a cell.. that should not happen in this country, not in this day and age," they said.
They said their grandson told them the overcrowding was in the main prison.
"He’s ok he’s in his own cell. The issue seems to be in the main prison because he’s in the progression unit. He hears stories that there’s trouble going on in the main prison as prisoners are not happy about it," they added.
In a statement, the Irish Prison Service said it must accept all prisoners committed by the courts and therefore has no direct control over numbers.
Numbers have surged by 14% or close to 558 additional prisoners compared to April last year.
The Prison Service said capacity in the system is 4,409 but 4,571 people are currently in custody, resulting in 167 prisoners having to be accommodated on the floors of cells with other inmates.
The former governor of Mountjoy Prison, John Lonergan told RTÉ's This Week that overcrowding has been a problem for decades, but temporarily eased off during the Covid-19 pandemic.
"The courts are back to normal," he explained.
"You had a huge number of cases deferred, you had a huge number of people put on bail and the courts weren't operating to full capacity and the Prison Service itself, because of Covid, was able to release people."
The prison service said significant capital funding has been provided by the Government to enhance existing infrastructure, with new male and female prison accommodation being built in Limerick, which has experienced significant levels of overcrowding in recent years.
This will result in an additional 90 spaces for men and 22 female cell spaces and is expected to be operational early this year.
However, Mr Lonergan said that he believed it was now time for the Government to introduce legislation that would allow prison numbers to be capped.
He said: "Increasing prison spaces is not the answer because we know, and from research all over the world, that if you create spaces, you'll increase prison populations.
"We don't need more people in prison, what we need to do is to have more alternatives and to divert people away from prison."
He said diverting people from prison should focus on those sentenced to 12 months or less, but would rely on having proper resources at community level and for the Probation Service.
The Irish Penal Reform Trust has made a similar call on the Government to use prison as a last resort, not only for those serving shorter sentences but also for those held on remand or eligible, where appropriate, for early or temporary release.
Mr Lonergan said this was never likely to be a popular political policy for governments whose main interest was often being seen to be a Government of law and order: "The popular thing is always more imprisonment and more punishment, but what's popular is seldom right and to do the right thing is seldom popular."
He said there were many negative consequences to ongoing prison overcrowding, including the potential for an increase in bullying and sexual assault as well as preventing access to education programmes and addiction services which can help prisoners' rehabilitation on the outside.
Additional reporting Eleanor Burnhill
