Julie Inman Grant told Tuesday's Senate estimates committee the rate was even higher among women and Aboriginal, Torres Strait Island and LGBTIQ communities.

Race, gender, disability and sexual orientation were the most common factors in the abuse.

Ms Grant said her office had a 100 per cent compliance rate with social media companies when it came to having harmful content removed online.

She said material, which could include child pornography or violent images, could be removed as quickly as within 30 minutes or as long as 24 hours.

When it came to dealing with social media companies, Ms Grant said she borrowed from American president Theodore Roosevelt's "walk softly and carry a big stick" approach.

She said the office had also issued 16 "abhorrent violent material" notices against "the worst of the worst underground sites" and still had a 75 per cent success rate in getting the material taken offline by those sites.

Ms Grant said her office had 90 per cent success in getting more than 150 overseas websites to remove revenge porn.

"So that's providing relief to victims in real time," she said.

She said 42 per cent of children had access to an internet-enabled device by the time they were two, with 81 per cent of parents handing over devices by the time their kids were four.

The office was trying to engage with parents early about the importance of online safety and their digital rights.

Australian Associated Press