Charities are calling for greater oversight of social media live streaming after reports children are being groomed through it.
Research by the Internet Watch Foundation on images and video captures of live-streamed child sex abuse found 98% of victims were aged 13 or younger.
Barnardo's research also found children too young to use the services were logging on.
The charity says urgent action is needed to protect children now.
Popular social media services including Facebook Live, Instagram Stories, Youtube and Snapchat all have a minimum age limit of 13.
In a sample group of 1,000 children between 10-16 years old, 85% of respondents under 13 admitted accessing live streaming sites. The survey was conducted by YouGov for the charity.
Chief executive Javed Khan said tech companies were "simply not doing enough to keep children safe" and has asked for a better age verification on live streaming websites.
The Internet Watch Foundation conducted an investigation between August and October 2017, where it discovered 2,082 sexual abuse images sourced through live streaming.
Of that sample group, 28% of the children were between seven and 10 years old, and 69% of the victims were between 11 and 13 years old.
The report added that "none of the imagery identified in the study included the physical presence of an adult".
The majority of the images and videos captured were when a child was unsupervised in their bedroom or bathroom with the door closed.
Chief Constable Simon Bailey, who leads on child protection for the National Police Chiefs' Council, said: "Parents need to talk to their children about how to stay safe online and make sure that they have the confidence to speak up if they are approached by a stranger."
In 2017 the IWF found 69% of images analysed were on image host distributors outside the UK, which exploits a legal loophole meaning the "core websites remain online and immune to takedown".
"Live streaming is being used by predators to groom children online," Mr Khan said.
"Children use live streaming apps that are not appropriate for their ages so tech giants need to ensure they put robust age-verification rules in place."
Mr Khan's comments come after Culture Secretary Matt Hancock said he was interested in introducing new laws to tackle the internet "Wild West" culture.
On Sunday he told BBC One's Andrew Marr Show, presented by Emma Barnett, that the government "just don't know" how many children of the millions using social media were not old enough for an account and he was "very worried" about age verification.
Mr Bailey said internet companies needed to make sure that there were the "necessary measures in place to prevent abuse happening on their platforms".
How to report child sex exploitation
If you're worried that a child or young person is at risk or is being abused you can contact the children's social care team at their local council. You can choose not to give your details.
You can report it online to the Child Exploitation and Online Protection command (CEOP).
Or you can call the NSPCC 24-hour helpline on 0808 800 5000 for expert advice and support.
If a child is at immediate risk call 999, or call the police on 101 if you think a crime has been committed.
Children and young people can call Childline free on 0800 1111 where trained counsellors are available 24 hours a day, every day.