Education Minister John O'Dowd has come under fire for approving a new Irish school with just 15 pupils as 2,500 teachers and support staff face losing their jobs.
The Sinn Fein man has been told he must make cuts of £198m to his budget.
His director of finance Trevor Connolly earlier this month described the situation as "extremely bleak", and department advisers urged him not to approve the establishment of the new school, but the minister has stood over his decision.
Coláiste Dhoire, proposed to be located in Owenbeg on the outskirts of Dungiven, Co Londonderry, will be only the second State-funded Irish-medium secondary school in Northern Ireland, following Coláiste Feirste in Belfast. UUP MLA Danny Kinahan has questioned the decision. "In the middle of a budget crisis, Education Minister John O'Dowd has made a decision to approve the establishment of a new Irish language secondary school," he said.
"He has done so contrary to the professional guidance of his departmental officials and a host of educational experts."
The advice on the development proposal to establish Coláiste Dhoire recommended the minister should not approve the new school.
Mr Kinahan has demanded Mr O'Dowd explain why he disregarded this advice. "A Government minister has a duty and responsibility to make rational decisions for the benefit of society as a whole, taking due consideration of the need to be responsible in spending taxpayers' money," he said.
"If a minister decides to disregard advice from his departmental officials, he needs to have solid, defensible grounds for doing so.
"The Western Education and Library Board, the Education and Training Inspectorate and the Department of Education itself have all said that the proposal is neither affordable nor viable.
"St Patrick's College in nearby Maghera provides an Irish language unit and they also have objected to the new school proposal. Damningly, even the Ministerial Advisory Group, which published a report last month reviewing Irish-medium education, has said that approval of this proposal flouts its recommendations."
The development proposal also revealed that the initial intake at Coláiste Dhoire is projected to be just 15, which Mr Kinahan described as "ridiculously low for a secondary school". "It has been estimated that approximately 11 double mobile classrooms will be required at a cost of approximately £600,000 per year, with specialised accommodation increasing the cost," he said.
"This is an extremely serious situation and the minister must be held accountable for his actions."
Mr O'Dowd is standing by his decision and said he made it following careful consideration.
"I take very seriously my statutory duty to encourage and facilitate education through the medium of Irish," he said.
"While I note the advice of officials, I am the minister and is my role to make the final decision on all development proposals.
"I stand over my decision on Coláiste Dhoire."
Education Minister John O'Dowd defended his decision, saying: "I take very seriously my statutory duty to encourage and facilitate education through the medium of Irish.
"While I note the advice of officials, I am the Minister and is my role to make the final decision on all development proposals. I stand over my decision on Coláiste Dhoire."