The Taoiseach Michéal Martin says the numbers of Covid cases in 5 to 11 year olds have gone through the roof.
The Government decided earlier that children over the age of nine will have to wear masks in school, shops and on public transport.
Children in third class and above will have to wear masks in school, while mask wearing for people aged nine and above will be mandatory in shops and public transport.
The requirement in schools will start tomorrow.
However, if a class is mixed second and third class, only the third class students will have to wear masks, while the advice to parents is to reduce social contacts of children.