At least one Catholic secondary school in Londonderry could close under new plans set out by the Commission for Catholic Education.
It may be St Peter's High School or Immaculate Conception College, both of which have low numbers of pupils.
All Catholic post-primary schools in the city are expected to be linked together in a new Derry City Foundation.
A public consultation has been launched, which will run until May.
A decision is expected to be made by September.
It is envisaged that the Foundation will be in place by 2013, by which date it is expected Catholic grammar schools will no longer use academic selection.
The plans also include the provision for all schools in Derry to become co-educational.
Eugene O'Neill from the Council for Catholic Maintained Education said there was no wish to see schools close.
"We have surplus school places within the city, and we're anticipating they will rise.
"Within Derry City we have two schools that are at risk, and that may involve closure but it may involve the other schools in the city taking a look at themselves to see how they could sustain those schools.
"Within the group of nine schools in Derry there is no wish to see any schools close, so we hope that through this consultation process we will be able to establish whether or not we should continue to have nine."
In County Derry, secondary schools in Dungiven and Claudy are also expected to merge, but St Mary's in Limavady will remain.
The principal of St Patrick's and St Brigid's College in Claudy, Jack McCauley, said he was "looking forward to contributing positively and proactively to this debate".
"What we have got to go for is the very best outcome for all the youngsters, now and in the future, and I think that can be achieved most effectively by having two large schools which are sustainable and viable," he said.