Students at Queen's University, Belfast, and the University of Ulster have thwarted an attempt to reveal accurate religious breakdowns. About a quarter of undergraduates failed to respond to a survey that claims to show a Catholic majority at Queen's and on the Ulster campuses.
A table of the bare statistics shows, at Queen's: 34 per cent Catholic; per cent Protestant; 2 per cent "other"; and 37 per cent not known or unavailable.
For Ulster there were: 41 per cent Catholics at Belfast; 46 per cent at Coleraine, 45 per cent at Jordanstown and 65 per cent at Magee. The figures for Protestants were 37 per cent; 41 per cent; 34 per cent; and 12 per cent, respectively. Figures for "not known or unavailable" were between 10 and 20 per cent.
Religion is recorded only for Northern Ireland-domiciled students, but the ratio of foreign students, particularly from the Irish Republic, is believed to have shrunk in recent years while more Northern Irish-born students have opted for home institutions.
Unionists in the Stormont Assembly clashed, however, over allegations of a "chill factor" militating against Protestants in higher education.
Edwin Poots of the Democratic Unionist Party urged employment and learning minister Carmel Hanna to tackle the take-up level of third-level education by Protestants.
But Ms Hanna said the accuracy of the tables could not be guaranteed because an average of 26 per cent of students had not responded.
"Religion is not a factor in the universities' admissions procedure. Under section 75 of the Northern Ireland Act 1998, universities have a duty to ensure equality of opportunity and a neutral environment," she added.