Deputy First Minister Martin McGuinness has said he will ensure a promised cancer centre for the north west goes ahead, but he sparked a row by claiming the decision to drop the plan was sectarian.
Ulster Unionist Health Minister Michael McGimpsey controversially announced on the last day of the Assembly that he was shelving the scheme, which was to serve patients in areas across the border including Londonderry, Donegal and Tyrone.
The Irish government, Sinn Fein, the DUP and other parties have pledged to work towards re-establishing the project after the May 5 Assembly elections.
Mr McGimpsey has been locked in a row with the larger Stormont parties over claims he received insufficient funding in the recent Assembly Budget. This is denied by the DUP and Sinn Fein.
The Health Minister has insisted he cannot afford to give the unit the green light, but Mr McGuinness told the BBC he believed the decision was "shameful, highly political and sectarian".
He added: "I would urge people not to panic. If you can be sure about anything in life, you can be sure that this radiotherapy centre will be built. I will ensure and guarantee that it is built."
Unionist representatives attacked Mr McGuinness for suggesting sectarianism played a role in the decision. Supporters of Mr McGimpsey said his decision was forced by finance, while even his critics dismissed the accusation of sectarianism and noted that the failure to press ahead with the unit would hit both Catholic and Protestant cancer sufferers.
East Londonderry MP Gregory Campbell said: "There has, quite rightly, been outrage across the community in the entire north west at the Health Minister's decision.
"The decision was party political and speaks volumes about the minister. There is now however grave risk to the unity of that campaign against the minister's decision by Sinn Fein's view that it was made for 'sectarian' reasons."
The DUP representative added: "This is a deeply unfortunate turn of phrase which jeopardises the unity of the opposition to the decision. It will not however deter us in the DUP from campaigning to have the decision reversed on the basis of need rather than this inaccurate and offensive use of language."