Joe Costello was speaking after a visit to Full Sutton jail in York, where the four Deputies met six terrorists, including members of the "Balcombe Street gang", for more than an hour.
The visit came amid growing tension over the fate of Republican prisoners on the mainland, seen as a potential stumbling block in the Northern Irish peace process.
Full Sutton inmates were concerned that the "dirty protest" by IRA prisoners at Whitemoor jail in Cambridgeshire may hamper their chances of transfer to Ireland, said Mr Costello.
Speaking after the visit, Mr Costello said: "We had a thorough and frank discussion with the prisoners. We now hope to highlight [their] changing and deteriorating circumstances."
Mr Costello said: "Their main complaint was that only four visits could take place at a single time and one has to apply in advance for these to take place. The pressure for getting into prison means there is a huge queue."Reuse content