The plight of meat factory workers was described as a "tale of woe" as unions appeared at the Oireachtas special committee on Covid-19.
Representatives of workers gave evidence to the committee, saying they were "petrified of catching Covid-19" and scared to speak out.
The recalled committee was discussing meat plants after clusters in Kildare, Laois and Offaly led to travel restrictions and business closures being imposed across the midlands.
Greg Ennis of Siptu told the committee that the situation with regards testing was "a tale of woe".
“I have seen situations and be made aware of situations where workers have been tested and allowed back into the workplace, and they didn’t get the results in some cases for four or five days.
"I believe some workers who were tested last week were allowed back into the workplace," he said, saying that workers feared retribution if they spoke out.
"I have never seen an industry where workers are so reluctant to come out front and talk to the media or to union officials about their concerns and that is a scandal."
Patricia King of the Irish Congress of Trade Unions said that it was "untenable" that the Health and Safety Authority was not automatically notified by a workplace if an employee contracts the virus.
"If we have the HSA charged with the protection and the prevention of injury to workers in workplaces, and they’re not even notified, they don’t do the inspections, they don’t go to the place to find out what happened, they don’t go to give advice as to what should happen to prevent it again, then, we will arrive in all sorts of a mess.”
The committee also heard that some Romanian workers had been unable to access social welfare because they had been registered as self-employed in Poland.
Nora Labo of the Cork Operative Butchers’ Society said that she was aware of agencies which hired workers from both Brazil and Eastern Europe.
"I mostly know about workers sourced from eastern Europe but there are also agencies that bring in workers from Brazil, for instance.
"I do not know how many agencies there are. There may be up to a dozen, but I do not think it is very relevant because they all have similar practices.
"These agencies are based in Ireland. Even when the agency to which I referred was working through its Polish subsidiary, the workers were hired and were always in close contact with the agency's Irish staff, though all the financial and contract business was done through the Polish subsidiary to evade tax in Ireland.
"From the beginning, people were in contact with the Irish staff of this agency, which is based in Waterford and was started in Ireland.
"The people who are described as Polish self-employed contractors in their contracts have no ties to Poland, are not even Polish and had never set foot in Poland.
"They are insured in Poland but they are actually Romanian."
Ms Labo said that the workers were "cheated" out of their social protections and were not able to access GP care or Covid illness benefits.
However, the meat industry defended itself, saying that the issue is "not all at its door".
Philip Carroll of Meat Industry Ireland told committee that clusters "don't start in meat processing plants".
"Covid is introduced into meat plants," he said.