The trade union Mandate has reiterated its warning to Tesco, that workers will go on strike if their pay is cut by the company.
Mandate says Tesco workers will go on strike if the supermarket chain goes ahead with the controversial plans to cut the wages of some long serving staff.
It comes as the Dublin Council of Trade Unions held a march and a rally in Dublin city centre earlier.
Hundreds marched down O'Connell Street calling for solidarity and support for workers' rights.
Mandate general secretary John Douglas said that Tesco are not treating some employees fairly.
"The workers in Tesco decided that they would vote for industrial action," he said.
"We have a mandate for industrial action. We've served notice on the company that if they attack our members on the 16th of May, that our members will be on strike right across this country."
Tesco has opened a voluntary redundancy scheme and has deferred reductions in pay and conditions until May 16.
The company has said that it remains open to constructive discussions in the Workplace Relations Commission.