Over €1.6m in unpaid wages has been returned to staff since the start of last year.
It's after the Workplace Relations Commission (WRC) carried out over 6,000 inspections of businesses.
Large amounts of withheld wages were returned to staff in the food, retail and construction sectors.
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Sinn Féin's workers' rights spokesperson, Louise O'Neill, says a lot more money is due to employees.
"I think it's the tip of the iceberg to be honest," she continued.
"I think if the WRC had more resources it would be in a position to carry our more investigations.
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"A lot more needs to be done to make workers aware of their rights.
"And we need to ensure that the WRC is more adequately resourced so that money can be recovered for workers."
