There are calls for the courts to only commit serious criminals to prison during the Covid-19 pandemic.
The Irish Prison Service says none of the nearly 3,800 inmates in jail have tested positive for coronavirus.
It has reduced the prison population by over 400 during the crisis.
But Fíona Ní Chinnéide, from the Irish Penal Reform Trust, says more measures are needed.
"It is absolutely critical that the committals to prison are reduced because this just puts further pressure on a system which is only running at operational capacity now, it's not running below that," she said.
"Prisons should be reserved for serious offenders who present a serious risk to society and particularly community-based sanctions should be used as an alternative for offenses that would attract a sentence of 12 months or less."