The High Court is to rule on a claim by Real IRA leader Michael McKevitt that he is entitled to one third remission of his sentence for good behaviour.
The 59-year-old from Beech Park, Blackrock, Co Louth was jailed for 20 years in 2003 for directing terrorism.
Michael McKevitt is looking for a third off his sentence under an enhanced remission scheme.
However, when he applied for early release the Justice Minister turned him down – a decision the Real IRA leader is now challenging in the courts.
His lawyers argue he is a model prisoner who has satisfied the rules of the remission scheme by engaging in structured prison activities that would make him less likely to re-offend on his release.
The State says the minister is allowed to have regard to the fact that McKevitt is a spokesman for republican prisoners, has committed serious offences and may be at risk of re-offending if let out.
The High Court will rule on the case later this morning.