RTÉ News has learned that a significant disturbance took place at the Midlands Prison in recent days in which dozens of prisoners refused to leave the exercise yard after many had first smeared their cells with human excrement.

RTÉ's This Week programme has learned that the incident involved 50 prisoners, who were protesting about their access to the yard.

Access to the exercise yard at the Midlands Prison has been curtailed as part of changes introduced under what is called a Regime Management Plan, which was put in place to cope with reduced staffing levels.

Prison management feared the incident would turn violent, but it passed off without anyone getting injured after officers entered in riot gear.

Prison staff from Portlaoise Prison were called in to back-up the operation.

The Irish Prison Service confirmed to RTÉ's This Week that an incident did take place last Friday, involving 50 inmates.

The IPS also confirmed that a new regime management plan had been implemented, which involved maintaining the safest operations.

The IPS said it was working to address a staff shortfall in the Midlands Prison, but it also added that there was an increased demand on prison officers to escort to courts, which also affects the availability of staff in the jails.

Speaking to RTÉ's This Week, the President of the Prison Officers' Association Tony Power, who is also a prison officer at the Midlands Prison, said the issue was of great concern to the POA.

Mr Power said the incident showed there was a "complete breakdown of law and order" as a result of staffing levels across the prison service.

He said it was inevitable that there will be more incidents similar to the one that occurred in Midlands due to regime management plans being brought in to match available staff with the resources in the prison.

This involved reducing access to the yard for inmates in the Midlands to maintain access to education and workshop facilities.

Mr Power said the POA was now seeking an "urgent engagement" with the IPS to see how it plans to deal with such incidents and to make sure the proper protective gear is provided to officers when called in to defuse potentially violent incidents involving large numbers of inmates.

He said the POA was "deeply concerned" that this was an issue likely to reoccur in the current staffing climate in Irish prisons.

Mr Power said he was calling on Minister for Justice Charlie Flanagan and the IPS to explain how they intend to deal with the emerging issue and to maintain prison officer and inmate safety.