Real IRA leader Michael McKevitt will have to wait until at least next week to hear if he will get out of jail early.
Judge Bernard Barton told Dublin's High Court he was reserving judgment on an application for remission until a separate case is heard in a higher court.
The Supreme Court is hearing an appeal about another prisoner who was let out of jail early under good behaviour rules.
Judge Barton said this ruling would deal with McKevitt's claim to be let out. McKevitt's case has been put back until next Monday. Judge Barton also refused a bail application.
McKevitt was jailed for 20 years in August 2003, convicted of directing a terrorist organisation and being a member of the Real IRA. The sentence, handed down by the non-jury Special Criminal Court, was backdated to 2001.
Lawyers for McKevitt argued he was entitled to remission, reduced imprisonment of one-third rather than the usual quarter. But barrister Diarmaid McGuinness SC, representing the State, said the minister had to determine the inmate's likelihood of reoffending.
The Supreme Court is expected to meet on Friday to rule on the legality of a High Court decision last month to free Eddie Ryan Jnr, the son of a murdered Limerick gangster, who was jailed for weapons offences.
Belfast's High Court ruled in 2009 that McKevitt and three other men were responsible for the 1998 Omagh bomb.