ST Colm's High School in Twinbrook has been forced to close to pupils until at least Thursday due to problems with their heating system.
Pupils have been asked to work from home using Microsoft Teams and students due to sit exams this month have been encouraged to continue with revision at home.
In a letter to parents which was posted on their Facebook page, principal Adrian Walsh said: "I have been advised that the school heating system will be completely out of operation until Wednesday evening, at the very earliest.
"Therefore, I have decided to use tomorrow as a staff training day which means pupils are not required in school. I am hoping that school will return to normal on Thursday but I will keep you up to date with developments.
"I have asked teachers to provide work online using Microsoft Teams and all pupils should have a C2K login and password.
"Students who have examinations in the November Series should continue with revision and past paper questions which they will have in their books/schoolbag.
"I assure you that I have not taken this decision lightly and I am sorry for any inconvenience.
"Thank you for your continued support."
