Schools should continue to provide Religious Education (RE) based on the “holy scriptures”, according to the Department of Education.
They are also legally required to hold collective worship like assemblies each day.
Education Minister Paul Givan has provided the guidance in a letter to school principals.
His letter is in response to a UK Supreme Court judgement that the Christian focused RE taught in Northern Ireland was unlawful.
Givan said in his letter that the judgement was complex and could not be ignored.
He said that it had ruled RE had not been taught in an “objective, critical and pluralist manner, and that collective worship was similarly not conveyed in such a way”.
But he said that the judgement had not struck down existing legislation.
“Schools will note, therefore, that both Religious Education and collective worship continue to be a legal requirement,” Givan wrote.
He also said the judgement recognised that Christianity is the main religion in Northern Ireland, and the greater part of RE would still focus on knowledge of Christianity.
But he said the RE syllabus would be reformed and he would set out how soon.
“The area of collective worship requires further consideration,” the letter continued.
“While parents have the right to withdraw their child, the Supreme Court found that current arrangements did not meet legal requirements.”
Givan’s letter stated that he would provide further comprehensive and “legally sound” guidance to schools in the coming weeks.
But it also said the department had “requested further legal advice to understand the full implications of the judgment”.