It is no longer true to say that all workers are being protected by the terms of national agreements, the leader of the country's largest trade union Siptu has said.
In an interview in advance of of its national conference in Tralee this week, Jack O'Connor said there were now whole sectors of the economy where the quality of employment conditions were deteriorating and where pay levels were actually falling, both in nominal and real terms.
He pointed particularly to the hotel and catering sector, which employs around 120,000 people, but maintained that similar trends were emerging elsewhere.
Mr O'Connor said that in the hotel and catering sector price rises were running at around the rate of inflation - nearly 5 per cent - but that wages paid to staff were on average declining.
"If you look at the Central Statistics Office figures for average earning for the year to December they increased by 0.7 per cent, much less than the [ pay rises under the] national agreement, much less than the rate of inflation. If you look at them in the year to March '07, they increased by 1.4 per cent. To summarise it crudely, it was 3.6 per cent less than the current rate of inflation.
"But if you compare figures for the end of the March quarter to the end of December, it is even worse. You have a net reduction of a nominal pay over that quarter of 0.8 per cent," he said.
Mr O'Connor also pointed to another set of statistics - regarding the distribution of workers from overseas in the Irish economy. He said that these showed that the rate for the hotel and catering sector was running at 29 or 30 per cent, around twice that of the next category.
"We see average nominal pay falling, real pay falling dramatically, very high percentage of new national workers and very high percentage of agency workers," he said.
Because national agreements were voluntary, there were employers "who are now discovering that they can disregard it with absolute impunity, via principally the exploitation of migrant labour".
He said that some employers were simply not paying the wage increases to staff, or were using the restructuring in the sector - "as you take the Jurys or Berkeley Courts, where people had unionised rates, out of the picture" - to bring in new employees at or around the minimum wage.
"There has to be some explanation for those figures. In order for those figures to be occurring you have to assume there are people who worked there all their lives, not just in unions, who are getting those [ national agreement] increases, and there are people who are doing a little better on the managerial side and so on. But if we are to eliminate them, how much lower are the people coming in at in order to provide for that average," he said.
The Siptu president has been a strong advocate of strengthening the rights of migrant workers and particularly those recruited through employment agencies.
Mr O'Connor has regularly highlighted that Ireland, the UK and Hungary were the only countries in the EU where it was legally permissible for agency staff to be paid less than regular employees.
"We have to accept that being one of only three countries in the EU that does not legislate for equality of treatment is wholly incompatible with the concept of social partnership. That has got to be faced up to by the Government."
He said there were various models of such legislation throughout Europe which could be discussed, but the principle of introducing such a measure had to be addressed.
Mr O'Connor acknowledged that a draft Bill to regulate employment agencies - which stems from a commitment in the most recent national agreement, Towards 2016, "could represent a measure of improvement in the current situation".
However, it has emerged in recent weeks that the EU Commission had raised concerns about the Bill, particularly regarding the obligation this would place on agencies to establish an office in Ireland. Unions fear that if agencies can operate from abroad they will be outside the scope of Irish law.