Fourteen Garda sergeants are taking High Court action because they were not granted normal subsistence allowances during their temporary transfers to the Garda Training Centre at Templemore, Co Tipperary.
Gardai attending Templemore do not receive their normal subsistence allowances and yet are required to pay for their meals, Mr Michael Cush SC, for the sergeants, told Mr Justice Kearns.
Some of the sergeants involved in the proceedings are now retired and all are or were stationed in Cos Wexford and Cork.
Garda members who are temporarily transferred to places other than Templemore receive a daily allowance of £56.79 for the first 14 nights, provided there are no sleeping and "messing" facilities available. Where there is sleeping but no messing, the allowance is £32.08 for the first 14 nights.
At Templemore, where the authorities contend that there are both sleeping and messing facilities, unmarried gardai receive 81p for the first seven nights, while married gardai receive £10.28 for the first 30 nights.
Mr Cush said the significantly lower allowances accorded to members attending Templemore were being defended by the Garda authorities on the basis that there were messing facilities there.
His case was that the facilities at Templemore were not a "mess" and, if they were, his clients ought not to be required to pay for food consumed there and at the same time have their subsistence allowances reduced.
The allowance provided for Templemore was arbitrary, capricious, invidiously discriminatory and unlawful, he said. The concept of "messing" related to a time when gardai were stationed in barracks and was a modern-day anomaly, Mr Cush added.
The issue the court had to decide was whether there was a "messing" facility at Templemore. If the answer was no, his clients won.
If the court found there was such a facility, his case was that this produced a wholly anomalous position which made the regulations allowing for different subsistence rates in such circumstances in excess of the powers of the Garda authorities, capricious and arbitrary.
The defendants - the Garda Commissioner, the Minister for Justice, Equality and Law Reform, and the Attorney General - deny the claims and maintain that messing facilities are provided at Templemore.
They deny that the subsistence allowance provided is discriminatory, capricious or unlawful.
The hearing continues today.