Its first guidelines on the use of TVs, computers and smartphones by under fives were published today.
The recommendation contrasts with UK experts at the Royal College of Paediatrics and Child Health, which said in January there was not enough evidence to confirm screen time was harmful to child health at any age.
Children’s commissioner Anne Longfield has said she believes guidance is needed as the use of smartphones and tablet devices increases.
The WHO report admitted there is “moderate to very low quality” evidence linking screen time and adverse health, such as childhood obesity. But it said habits formed in childhood influence activity levels throughout life.
The organisation said watching TV or videos or playing computer games was “not recommended” for children under two. For those between two and four, it should be no more than an hour, and “less is better”. Parents or carers should engage the child in reading or storytelling instead. It also said children aged one and older should have at least three hours of physical activity a day, including an hour of “moderate to vigorous intensity”.
Professor Andrew Przybylski, an internet expert at Oxford University, said the conclusions were “out of step with scientific evidence of harm”.
He said: “Both the American Academy of Pediatrics and the Royal College of Paediatrics and Child Health now emphasise that not all screen time is created equal. It might have positive effects on the family system as a whole, for example freeing up parents to do necessary household tasks and provide young people benefits such as relaxation, low energy play, or communication with family.”
Dr Tim Smith, of the Centre for Brain and Cognitive Development, Birkbeck, University of London, said: “In recent months UK parents …have been bombarded with conflicting recommendations and guidelines … The new WHO guidelines do not help to clarify the situation.”