Convicted Real IRA member, Michael McKevitt's application for early release has been adjourned until tomorrow at the High Court.
Mr McKevitt is looking for a one-third enhanced remission of a 20-year sentence instead of the usual one-quarter remission.
If granted, he could be released immediately.
Lawyers for Portlaoise Prison are looking for a further adjournment until a related Supreme Court case is decided.
Mr Justice Bernard Barton will make a decision on that application tomorrow.
Mr McKevitt was jailed for 20 years in August 2003 after being convicted at the Special Criminal Court of directing a terrorist organisation and of being a Real IRA member.
His sentence was backdated to 2001.
Senior Counsel Michael O'Higgins has argued that a recent judgment ordering the immediate release of an IRA prisoner also applied to Mr McKevitt.
Earlier this month, Mr Justice Gerard Hogan ordered the immediate release of IRA prisoner Niall Farrell on the grounds he had not been given proper consideration by the prison authorities for a one-third remission of sentence.
This applied where he had been of good conduct and had engaged in activities to prepare him for release and re-integration into society.