Children who spend more than two hours a day in front of the computer or television are more likely to experience psychological difficulties, new research from Britain suggests.

The British study of more than 1,000 children aged 10 and 11 found children who spent more than two hours daily watching TV or on the computer had higher psychological difficulty scores.

The link, observed even among kids who were physically active, was strong enough to prompt the authors to conclude that limiting children's screen time may be necessary.

"While low levels of screen viewing may not be problematic, we cannot rely on physical activity to compensate for long hours of screen viewing," said lead author Angie Page, from the University of Bristol's Centre for Exercise, Nutrition and Health Sciences.

Researchers tested children's psychological health through questionnaires that rated their emotional and behavioural well-being.

The research was published in the November edition of the American journal Pediatrics.