Half of the world's children, or approximately 1 billion, are affected by physical, sexual or psychological violence, suffering injuries, disabilities and death, because countries have failed to follow established strategies to protect them, said a UN report.
The Global Status Report on Preventing Violence Against Children 2020, which covered 155 countries, found that while 88 % of countries have key laws in place to protect children, only 47 % said they were strongly enforced, reports Xinhua news agency.
The report published on Thursday also included the first-ever global homicide estimates for children under 18 years of age.
It found that around 40,000 children were victims of homicide in 2017.
"Violence against children has always been pervasive and now things could be getting much worse," said Henrietta Fore, Unicef Executive Director, in a statement.
"Lockdowns, school closures and movement restrictions have left far too many children stuck with their abusers, without the safe space that school would normally offer," she said.
"It is urgent to scale up efforts to protect children during these times and beyond, including by designating social service workers as essential and strengthening child helplines."
While around 83 % of countries have national data on violence against children, only 21 % used the information to set baselines and national targets to prevent and respond to violence against children, the report said.
With about 80 % of countries having national plans of action and policies, only one-fifth have plans that are fully funded or have measurable targets.
A lack of funding combined with inadequate professional capacity are likely contributing factors and a reason why implementation has been slow, according to the report.