SWIFTER action on wearing masks in schools would have spared teachers weeks of anxiety, a union has claimed.
New rules on face coverings come into force this week.
All secondary pupils and staff have been asked to adopt a policy of wearing coverings in communal spaces and corridors.
The guidance was published just days before schools reopened.
The Ulster Teachers' Union (UTU) said it was known for some time that the medical advice was that masks should be worn in public areas where social distancing may not be possible.
"It has always seemed counter-intuitive that they shouldn't be worn in similar situations in schools," said UTU president Stephen McCord.
"We welcome this decision, of course, but it could have been introduced two weeks ago and saved much anxiety, not only among teachers but also pupils and parents."
Mr McCord added that there is no specific guidance for parents dropping off and collecting children.
The guidance says that staggered arrival and pick up times "may be introduced" to limit interactions and avoid gatherings at school gates.
"These are all areas where people may not be able to socially distance, depending on the individual circumstances of the school, its location and lay-out of course," Mr McCord said.
"All this will be especially challenging as we enter the winter where so many children are affected by colds and coughs anyway.
"The guidance states that any child with any kind of respiratory issue, like coughing, should be isolated and tested immediately so we need to have those robust measures to hand.
"If it turns out to be Covid then again we need to have measures in place to protect others in the environment so we must have access to testing and tracing."
