The Royal Commission into Institutional Responses to Child Sexual Abuse has made a direct appeal to children in care to give evidence.

Commissioner Robert Fitzgerald addressed more than 100 children under 18, many of whom are in the child protection system, at a youth conference in Brisbane today.

He invited them to tell their stories and give advice to the commission based on their experiences.

"I, as a Commissioner, don't know how it feels to be in and out of home care," he told delegates.

"You've felt it, experienced it. You know what we need to do. Tell us."

Mr Fitzgerald said much of the evidence already heard in the royal commission involved historic allegations of abuse in schools, religious institutions and other organisations.

But with about 50,000 children moving in and out of care each year in Australia, he said it was important to hear contemporary accounts of their experiences.

He told delegates it was "important for you, but it's also important for kids to come, as well as holding those who have done the wrong thing to account".

Mr Fitzgerald invited young people to approach the commission with their stories, saying more than 4,000 people had already testified in private hearings.

"We'll respect it, we'll believe it and we'll support you in it," he said.

Tash Dale, a youth worker with conference organiser the Create Foundation, gave evidence to the royal commission earlier this year about her own and others' experiences of abuse in the care system.

She welcomed the commissioner's reassurances about how witnesses would be treated.

"That's a huge thing for children in care. We, growing up, believe that we're just foster kids and we're not going to be believed," she said.

"Coming forward is a huge step, it can be difficult.

"It's not going to change their past but it can change somebody else's future."

The royal commission was set up by the Gillard government in early 2013 to run for five years.

It moves to Adelaide this week and next month will examine allegations of abuse at two Brisbane schools during hearings in the city.