A Labour Party delegation which visited Irish prisoners in Britain is calling for an inquiry into prison conditions by Amnesty International and the EU Committee for the Prevention of Torture.
The four member delegation, which visited prisoners held in high security jails, said that conditions had deteriorated considerably in the period since the IRA called off its ceasefire and resumed bombing in Britain.
The leader of the delegation, Mr Joe Costello TD, said that any further deterioration in conditions could have a "negative" effect on the peace process.
Mr Costello said that the prisoners felt they were being used as "hostages in a political game being played by the Home Office and British government as part of a political agenda".
He said: "There is huge frustration and annoyance at the deteriorating conditions. This came across at all prisons. The prisoners that we spoke to about the peace process indicated that, while they are in favour of a ceasefire, they certainly do not want a situation to arise where there are obstacles or preconditions introduced for the future. That could not be tolerated."
Senator Sean Maloney expressed particular concern about the impact of greatly increased restrictions on Irish prisoners in special secure units, which he described as prisons within prisons.
In these units, he said, inmates were kept in their cells for 23 hours at a time and were subjected to repeated body searches during the day. There were also regular checks on their cells at night.
One prisoner had told him prison officers entered his cell and turned on the light 18 times, in one night. The prisoners were refusing visits from their families because of the security measures, involved.
The delegation, which included Mr Tommy Broughan TD and Mr Declan Bree TD, also called for the transfer of prisoners from British to Irish jails to be speeded, up.