One of the north's three Dominican grammar schools is to end the use of 11-plus tests completely within the next five years.
A proposal has been published which, if approved, would see Dominican College in Portstewart begin a "phased and complete transformation away from the use of academic selection" for admission of pupils.
The move is part of a wider plan involving Catholic post-primary schools on the north coast, which would also see St Joseph's College in Coleraine shut down and nearby Loreto College increase in size.
Dominican will become just the third Catholic grammar to abolish selection since the Church hierarchy asked all schools to end the practice.
The Catholic Church first told its grammar schools six years ago to phase out academic selection, and scrap all entrance tests by 2012.
So far, Loreto in Coleraine and St Patrick's Grammar School in Armagh are the only ones to have done so.
While the ending of selection at Dominican is being seen as significant, there are no plans for a similar shake-up in the order's Belfast grammar schools, Dominican College Fortwilliam and St Dominic's in the west of the city.
An ambitious new 'area plan' for Catholic schools in north Belfast will not involve Fortwilliam.
St Dominic's, meanwhile, has been the best-performing grammar school in the north for the past two years and has no plans to change its admissions policy.
The proposal for Dominican Portstewart involves it increasing its enrolment to 675 by the start of the 2018/19 academic year.
It will meanwhile phase out selection over four years, starting from September 2016.
In Coleraine, St Joseph's College will begin a two-year phased closure from September 2016.
The now all-abilities, non-selective Loreto grammar school will increase its enrolment from 848 to 1,150 over the same period.
Education minister John O'Dowd has said it appears there is evidence of "an irreversible trend" towards the end of academic selection, even though progress has been limited.
Two top-performing schools in Omagh, Loreto Grammar and Christian Brothers Grammar, have also said they want to phase out selection by ability, starting this year.
The move was hailed as a coup for the Church in its drive to abolish academic selection.
While this is still the Catholic trustees' plan, the actual timing has still to be established.
In addition, as it is still a proposed phasing out of selection, the schools are advising children to continue to sit entrance tests.
Elsewhere, a planned phasing out of selection at St Mary's Grammar School in west Belfast has been reversed.
Gerry Murphy, northern secretary of the INTO teaching union, welcomed the Dominican proposal.
"I would welcome the significant progress this represents for children in the Portstewart catchment area. However, it is still only incremental progress in respect of the wider issue of continuing selection," he said.
"We look forward to seeing an end to the injustice that using unregulated transfer tests represents for children across the north."
