Health Minister Stephen Donnelly has been told to intervene to ensure 35 children are provided with a life-changing cystic fibrosis drug.
They were refused the treatment following a disagreement between the HSE and the manufacturers, Vertex Pharmaceuticals.
The drug Kaftrio is being provided to 140 children in Ireland - but another 35 have been refused it.
Parents and children will protest outside Leinster House today.
Chief executive of Cystic Fibrosis Ireland, Philip Watt, says they are considering taking legal action.
"Every day their health is being compromised by the fact that they are not getting this drug," he continued.
"In fact it also opens the distinct possibility of legal action.
"This drug is available for every child except for these 35 children and delayed access is no access.
"It is causing a major problem."
