Some 320 million children globally have been locked out of school due to the COVID-19 pandemic, the United Nations children's agency (UNICEF) said on Tuesday as it urged for a reopening of learning facilities.

The agency said locking children out of school was only compounding the societal cost of the pandemic.

"What we have learned about schooling during the time of COVID is clear: the benefits of keeping schools open, far outweigh the costs of closing them, and nationwide closures of schools should be avoided at all costs", Robert Jenkins, UNICEF Global Chief of Education, said in a statement.

UNICEF noted that the school closures did not help in the fight against COVID-19, but simply removed a system that provides children with support, food and safety as well as learning.

It urged governments to instead prioritize reopening learning facilities in a safe manner tor learners.

"Evidence shows that schools are not the main drivers of this pandemic. Yet, we are seeing an alarming trend whereby governments are once again closing down schools as a first recourse rather than a last resort. In some cases, this is being done nationwide, rather than community by community, and children are continuing to suffer the devastating impacts on their learning, mental and physical well-being and safety," Jenkins said.

UNICEF cited a recent study using data from 191 countries, published by the independent non-profit foundation, Insights for Education, which showed no association between school status and COVID-19 infection rates in the community.