55 per cent of those aged 8 to 12 did not tell a parent when bothered, confused or upset by this content, rising to 63 per cent for 12-14 year-olds.
More than two thirds of primary school children have been contacted by a stranger during an online game.
A survey from CyberSafeKids has found a quarter of children in this age group have experienced harmful or upsetting content while online.
55 per cent of those aged 8 to 12 did not tell a parent when bothered, confused or upset by this content, rising to 63 per cent for 12-14 year-olds.