Mandate has extended its pickets on the German discount supermarket chain, Aldi, to the company's distribution centre in Sandyford, Co Dublin. It is also planning to picket the Aldi outlets in Cork and Letterkenny.
The Irish Congress of Trade Unions has granted Mandate an all-out picket in the dispute, which Mandate says is over union recognition and the sacking of five employees at Aldi's store in Parnell Street, Dublin.
The Dublin Council of Trade Unions passed a motion of support for Mandate at its meeting on Tuesday. It accused the company of "arrogance in not respecting the culture of the host country they have come to trade in by sacking staff for joining a trade union."
It added: "We further condemn their arrogance in refusing to respect the institutions of the State by refusing to attend a Labour Relations Commission conciliation conference."
A Mandate organiser, Mr Willie Hamilton, said there was a good response to the picket at Sandyford and several drivers had turned back. As the union has no members in Sandyford, Mandate volunteers from other workplaces are providing pickets.
A company spokeswoman denied the five staff members had been dismissed because they were in Mandate. She said that two had been on probation and were let go because their performance "was not up to standard". The other three had been dismissed after refusing to carry out cleaning and other duties provided for in their contracts of employment.
A full disciplinary hearing had been held, and they could still appeal the findings if they wished. She said the pickets had not affected business at Sandyford.
Aldi is a private German company with 5,000 outlets in 11 countries. It prefers to deal with employees directly. Its workforce is eligible to elect a European Works Council, but none has been established.
Aldi is planning to open further outlets in the Republic.