This advice has been strongly recommended for some time, but there have been reports from teaching unions that this has not been well followed.
The news comes as it is revealed that a quarter of secondary pupils are currently off school for various reason, including Covid.
All pupils will now be required to wear face coverings where physical distancing is not possible, such as corridors, but it still not envisaged that masks will be required in classrooms.
Masks will also be required by pupils using school transport. However, students will not be prevented from using school transport if they are unable to wear a mask.
If primary pupils want to wear masks, they will be supported.
In Special Educational Needs and Disabilities schools and settings, face coverings will be worn by staff and students when and where possible.
For those unable to wear a face covering, lanyards and exemption cards are available.
Education, Sport & Culture president Andrea Dudley-Owen said the committee was grateful that many secondary and post-16 students, staff, parents and carers had been wearing face coverings in recent weeks.
‘There has been, though, a noticeable lack of consistency among secondary students as a collective and staff across all our schools, so we have decided to strengthen our policy position on this,’ she said.
‘We know that face coverings are just one of the protective measures in place in education settings to reduce risk of transmission, but it’s important that we are all as vigilant as possible, especially in the run-up to Christmas, as we seek to continue living responsibly with Covid-19 with as little disruption as possible.’
Director of Education Nick Hynes said the move was proportionate to the risk.
He said that there were no plans to break up the schools early. Some parents have voiced a wish to take their children out of school.
Mr Hynes said there were mitigations in place to keep students and staff safe, such as well-ventilating classroom.
He added that if parents had specific concerns, they should speak to their child’s headteacher.
Typically at this time of year in pre-Covid times, primary schools would have 96% attendance and secondary 95%.
Currently there is 80% attendance in primary schools and 76% in secondary.
Only some of these absences are directly due to Covid or self-isolating.
Mr Hynes said staff were stretched and thanked them.
He appealed for any qualified teachers or teaching assistants who would be interested in additional supply work to contact the education office.