Fine Gael, Labour and the Greens are to table their third joint private members' motion since the Christmas recess.
The motion, to be debated next week in the Dáil, calls on the Government to reverse cuts to the social welfare entitlement of widows and widowers.
In recent weeks the Opposition joined forces to table motions on electronic voting and the status of the Irish language in the EU.
The latest motion says the entitlement of widows and widowers to additional disability, injury or unemployment benefits, based on their social insurance contributions, should be restored.
Notice of the motion comes ahead of a meeting next Tuesday between the Minister for Social, Community and Family Affairs, Ms Coughlan, and the National Association of Widows in Ireland.
Ms Coughlan's spokeswoman said she would go in to the meeting with an open mind.
"I don't know what, if anything, will come of it. She is going to listen to their case."
The Opposition motion says the Government will save only €6 million by introducing the cut.
Labour's social welfare spokesman, Mr Willie Penrose, said the cut was mean and nasty.
"It will create real problems for working widows and lone parents who lose their jobs or become ill.
"With tax revenue for the first two months running around €430 million ahead of the level forecast, there is absolutely no justification for this cut."
Fine Gael's Mr Michael Ring said widows and widower pension recipients who were paying tax on their pensions as well as their earnings were "faced with the shock" of realising they were not entitled to benefits in cases of accident or injury.