Thousands of Dunnes workers have placed pickets at stores across the country today.
They are protesting at the use of what they call "excessive" low-hour and temporary contracts.
The staff are represented by the union Mandate, which says the company is refusing to engage with them on the issue.
Tánaiste Joan Burton has told the Dáil that Dunnes management has not engaged with the State's industrial relations machinery.
"The issues in dispute have been before the Labour Court on a number of occasions and the Dunnes Stores management has not actually engaged in the industrial relations machinery," she said.
Meanwhile, the leaders of Fianna Fáil and Sinn Féin both turned out to show support for Dunnes workers in Dublin this morning.
Fianna Fáil leader Micheal Martin hit out at a 20%-off special offered by Dunnes Stores online today, and called it a "cynical" move.
"It appeals to the lowest common denominator to try and break the strike like that," he said. "I think people would recoil at that kind of a tactic. It's appalling."