The Irish Congress of Trade Unions has called on the Government to introduce a "fair and transparent regularisation process" to allow thousands of undocumented workers in Ireland to work here legally.
In a letter to Minister for Justice Brian Lenihan sent last month, the general secretary of Ictu, David Begg, said that the aim of such a scheme should be "to provide a bridge for workers out of their irregular situation back to a regular situation".
Mr Begg said that there were "many thousands" of undocumented workers now in Ireland and that the situation in relation to some of these was urgent.
"I have recently been made aware of the unsatisfactory situation of a large number of workers from Brazil who were brought to Ireland to work in the meat processing sector. The pressing situation of these workers calls for the introduction of an immediate response which will provide them with permission to remain and work until the regularisation scheme has been developed," Mr Begg stated.
He said that some form of regularisation scheme was necessary "if a growing underclass of workers in an irregular situation, who are vulnerable to exploitation, is not to be created".
He said that many undocumented workers had originally entered the country legally and had paid their taxes and made social insurance contributions but that their permission to work had not subsequently been appropriately renewed.
He said that in some circumstances this may have been due to a misunderstanding on their behalf or that of their employer. He said that in many cases the worker became undocumented through the inaction of their employer who simply did not renew their work permit.
"There is no benefit whatsoever in Ireland denying the presence of undocumented workers. Likewise it is wrong not to recognise the different circumstances that can lead to workers becoming undocumented and it is unfair not to make provision for a mechanism through which workers can regularise their situation.
"This is particularly necessary if we are to avoid the development of occupational sectors dominated by undocumented migrants, creating in the process an exploited working underclass," he stated.
Mr Begg sought a meeting with Mr Lenihan to set out proposals for a regularisation scheme.
The Irish Times revealed last month that the Government is to launch a research project to try to determine the numbers working illegally in Ireland following rising concern over the number of undocumented workers here.
Minister for Enterprise and Employment Micheál Martin said there were currently no hard figures and that he and Minister Lenihan would tackle the issue.
The Migrant Rights Centre Ireland has estimated that of 1,000 migrant workers who sought its support last year, about a quarter had become undocumented. Almost all had entered the country legally on a work permit.
Meanwhile it was reported yesterday that Ictu believes that the level of general immigration could be higher than that set out in official figures. Ictu has said that there is a commitment under the national agreement, Towards 2016, for the Government to research the numbers involved.
The recent census found that the number of Chinese immigrants in Ireland stood at 11,000. However, Ictu maintained that this was far short of the estimate of 100,000 put forward by some observers.