Bus and train workers are to strike for 24 hours on May 6.
All Ulsterbus, Metro and NI Rail services will be affected by the protest against cuts to public transport.
Unite regional secretary Jimmy Kelly said the elderly and infirm who depend upon buses and trains would be hurt by reductions to services by provider Translink.
"Unite estimates that the cuts to bus and rail services will save only £6-£7 million - a meagre sum in terms of the wider budget.
"Yet these cuts will compromise the integrity and inter-connectivity upon which Northern Ireland's public transport system rests.
"Our drivers and engineers are concerned that cuts to 'non-economic' services presage moves to break up and contract out profitable routes - a move that would undermine the 85% of routes that are non-profitable."
Mr Kelly said he was seeking a meeting with Peter Robinson and Martin McGuinness.
"The proposed cuts to bus and rail services being brought forward by Translink will impact the most vulnerable people in our society - including the old and infirm, those with families, the working poor, those living in isolated, rural communities who are dependent on public transport."
He said reductions were being proposed to hospital runs, shopping services, rural routes and town centre buses as well as to morning, evening and Saturday rail services on the Larne-Belfast and Newry-Bangor lines.
"These cuts will force increasing numbers onto the roads at a time when funding for roads maintenance budgets is being cut to the bone and roads maintenance workers confined to depots for lack of tar, concrete or diesel.
"There can be no excuse for these cuts at a time when the Northern Ireland Executive can find £325 million to fund the costs of achieving global tax haven status (reductions to corporation tax)."