A representative association described the earnings as “a national scandal”.

PDforra, which represents enlisted men in the Defence Forces — said it had completed a list of earnings of all the 250 members who had served on last year’s mission, and the breakdown on hourly earnings, including special allowances.

The organisation’s vice president, Mark Keane, said a database had been compiled and the association was preparing to furnish it to an arbitrator who, it was hoped, would decide on an increased allowance which PDforra believes the naval service ratings are entitled to receive.

The association argued the naval personnel should have been allocated the recognised overseas allowance for armed duties, as some had to carry weapons for security reasons. This allowance amounts to extra €25 a day.

The two allowances payable under the overseas peace support allowance (OPSA) work out at a standard rate of €55 per day for non-armed missions and €80 daily for armed missions.

PDforra said the crews should be paid the higher allowance as the ships are armed with powerful guns and, at various times on operations, personnel have to carry weapons.

“Typically in the Med during Operation Pontius they were working 16 to 18-hour days.

“When they had completed a rescue and dropped people in port, crews had to sanitise the ship before heading out again,” said Mr Keane.

He said senior members of the ships, such as chief petty officers who had an average of 20 years service and were the backbone of the crews, received on average €8.15 per hour after tax.

Last October, Minister for Defence Simon Coveney said he was willing to send the OPSA claim to arbitration.

Since then, talks on the issue between PDforra and civil servants in the Department of Defence have broken down.

Mr Keane said his organisation was now insisting Mr Coveney “live up to his word” and get an arbitrator appointed immediately to address the grievance.

The organisation’s vice president said the database compiled will be used by PDforra in its negotiations to secure increased pay for young entrants who currently get €21,850 a year.

“Don’t get me wrong, all of our members volunteered to go out there and were happy to save lives, even though it was very traumatic at times.

“But surely they should be given something better than what is regarded as less than the minimum wage for their efforts,” said Mr Keane.

“They are calling our lads ‘heroes’ but then treating them as second-class citizens by effectively paying them way below the minimum wage.

“Many of them witnessed harrowing scenes when they had to dive over dead bodies to rescue the living.

“They’re proud of what they did to save lives but there’s a high degree of frustration in the aftermath with what they have been paid,” he added.