AN all-girls school due to welcome boys as part of a shake-up of secondary education in west Belfast has failed to publish admissions criteria.
The Department of Education has warned that St Louise's Comprehensive College "may be acting unlawfully" by admitting any child on that basis.
Parents told The Irish News they had no idea what was happening with the deadline for applications looming.
An overhaul of Catholic secondary schools in west Belfast is already a year overdue.
Three single-sex post-primaries are to be merged into one new 1,000-pupil college.
In addition, St Louise's, once the largest school for girls in Europe, will admit boys and decrease pupil numbers to 1,500.
It was hoped arrangements would be in place by 2018, but were pushed back until September this year.
The plans were approved by department permanent secretary Derek Baker in July 2017.
The new school - All Saints College - brings together St Rose's Dominican College, Corpus Christi College and Christian Brothers' School (CBS).
It will initially operate on a split site with Years 8 to 12 at CBS and post-16 at St Rose's and "provide excellence in educational provision and outcomes for young people in the area".
While St Louise's is expected to admit boys, it has not published any admissions criteria for 2019 entry. The deadline for applications is February 6.
All post-primary schools were told to return criteria to the Education Authority by October 26 last year.
The department warned that failure to do this risked confusing children and parents.
Deadlines for admissions criteria, it said, were designed to give parents sufficient time to prepare for applying for places.
"Should a school fail to set admissions criteria that allow it to prioritise pupils for admission, the board of governors of that school may be acting unlawfully by admitting any child," a spokeswoman said.
"The failure to date of the board of governors at St Louise's Comprehensive College to set admissions criteria for September 2019 will only cause confusion for children and parents considering whether to apply to the school and this failure may lead to a scenario where no pupil can be lawfully admitted to the school in the event of oversubscription."
The school has so far not provided The Irish News with any comment.
It is understood, however, that work is continuing to ensure the changes take effect from September.
When the original plan was out for consultation, St Louise's governors said they supported it but needed a new building on the present site.
They added that full facilities must be put in place to cater for phased integration of boys. This would include money to allow the conversion of toilets and changing rooms.
