A son of slain Limerick gangland figure Eddie Ryan has brought a High Court challenge after he was refused extended remission on a six year jail sentence.

Eddie Ryan Junior (31), with a previous address at College Avenue, Moyross, was jailed by Limerick Circuit Criminal Court in 2010 after pleading guilty to possessing firearms.

The High Court has heard that his good behaviour in prison means he is eligible for release in November having served three-quarters of his sentence.

However his lawyers are arguing that he should have been freed last month under an extended remission scheme that allows the length of a sentence to be reduced by a third.

Colman FitzGerald SC, says his client satisfies all the criteria to qualify for the earlier release date having pro-actively engaged with every programme offered by the prison service to help inmates reintegrate into society and avoid re-offending.

He is arguing that the refusal of the Justice Minister to grant extended remission is 'legally defective' and rests on a mistaken belief that the statutory scheme is to be used 'sparingly' and only in 'exceptional circumstances'.

Judge Max Barrett has ordered an Article 40 inquiry into the lawfulness of Eddie Ryan's continued detention, which is due to be heard this afternoon.

Eddie Ryan Senior was an early victim of Limerick's feuding crime gangs. He was gunned down while drinking in the 'Moose Bar' in November 2000.

His two sons - Kieran and Eddie - were reportedly abducted in 2003 but turned up unscathed several days later.