Up to 20 workers on a major construction project in Athlone Co Westmeath began a protest outside the site this morning.
The men, who are all Polish nationals, were working as general operatives with a subcontracting firm on the 23,000sq.m Athlone Town Centre shopping complex.
SIPTU is representing the men and has been making complaints of underpayment for several months.
The union claims many of the men were let go last Friday because they refused to drop their complaints.
The unofficial protest is taking place because the company in question has refused to deal with the issues using the normal industrial relations process, according to a spokesperson for SIPTU.
