Most adults in Northern Ireland do not know when children are old enough to be using social networks such as Facebook and Snapchat, new figures suggest.
Nearly six in ten (59%) did not realise the sites required users to be 13 or over, an NSPCC survey found.
A fifth thought there were no age requirements at all.
Neil Anderson, head of NSPCC in Northern Ireland, said: "Age restrictions need to reflect the content and conduct possible on each site and be crystal clear to parents and their younger users.
"And platforms need to work harder to protect children and young people, building in child safety to the design of each site.
"Parents can be proactive by having conversations with their children about online safety as soon as they start using the internet."
Calls to the NSPCC's Childline service showed that children under the age of 13 were using social networks and in some cases having negative experiences online.
One 11-year-old caller told counsellors: "I'm really upset; the other day my friend showed me some horrible pictures that people were posting on Instagram of me.
"Some people at school have taken pictures of me and put silly tags on the pictures and put funny faces over mine.
"I've been bullied before and now it's on Instagram and I can't seem get away from it and everyone else can see it too."
And a 12-year-old girl who contacted Childline said: "I was playing dares with a boy from my school then he dared me to send nudes and I did.
"I feel ashamed and embarrassed and I don't know why I did it.
"Now I have fallen out with him he has sent the photo to everyone all over Instagram and Facebook and Snapchat and I keep getting abuse at school and online saying I'm rotten and a slag."