Caitriona Ruane has warned a leading grammar school against plans to set up its own entrance tests once the 11-plus is scrapped later this year.
In a strongly-worded letter to Pat O'Doherty, the principal of Lumen Christi College in Londonderry, the Education Minister branded the college's announcement last month "a very unhelpful contribution".
The Catholic maintained school has said it will introduce a two-part aptitude test because of a lack of guidance from Ms Ruane.
In the hard-hitting letter obtained by the North West Telegraph, the Minister said she was "very disappointed" that the school was proposing such a course of action.
Ms Ruane also sent a similar letter to 40 feeder primary schools in the Derry area in which she told them to concentrate on delivering the revised curriculum. The Minister also told them that no post-primary school can oblige a primary school to prepare pupils for any particular feature of its admissions process.
Bishop Seamus Hegarty, who is a senior trustee for Catholic schools in Derry, has already criticised Lumen Christi's plans.
It is understood that principals of up to 30 grammars across Northern Ireland will meet this week to reveal if they too are willing to act against the Minister's wishes and retain academic selection by setting their own tests. However, Lumen Christi is the only grammar school the Minister has written to.
"Academic selection, independently developed and operated by schools, and based on entrance tests, is a prospect fraught with administrative and litigious perils," Ms Ruane warned Mr O'Doherty.
She went on to praise the "robust and secure testing mechanism" of the current Transfer Test developed and operated by local exams body CCEA.
The two-page letter also states: "Should the College proceed with its proposal, it will not only need to fund the test itself, using resources that I would argue could be better used for young people's education, but it must also be sure that it can independently manage the host of risks, pressures and challenges that will accompany the test.
"The Board of Governors should be in no doubt that the Department of Education will
not fund, facilitate or in any way support a breakaway entrance test. Nor will the Department allow any interference with the delivery of the revised curriculum in primary schools."
The Minister said she did not want to see schools get into administrative or legal difficulties over the matter.
"I would therefore urge the College to reconsider its decision, not just because of its practical implications but also because of the need for greater social justice in school admissions - a point that has been urged upon the college by one of its senior trustees, Bishop Hegarty."
Mr O'Doherty was not available for comment this morning.
Sir Kenneth Bloomfield, from the grammar school group the Association for Quality Education, said the Minister was putting pressure on schools to come into line.
He added: "However, we have to remember that when wider opinion in Northern Ireland has been tested the majority have favoured an alternative method of academic selection."
The Belfast Telegraph revealed last week that Sinn Fein is considering bypassing the Assembly to introduce a controversial new school transfer system in place of the 11-plus.
A leaked Sinn Fein briefing paper was passed to this newspaper by Basil McCrea, education spokesman for the Ulster Unionist party.