Victims groups are bracing for a flood of people wanting to give evidence about child sexual abuse, as the royal commission holds its first sitting in Melbourne this week.

The royal commission into child sexual abuse will outline how it plans to deal with the sensitive nature of the evidence at the session at the County Court of Victoria on Wednesday.

It will not take evidence, but the sitting will be the first major update on how the commission will work since the six commissioners were appointed in January.

Tens of thousands of Australians are expected to come forward over the three years of the inquiry to tell their stories of abuse in institutions such as schools, churches and orphanages.

Given the huge workload for the commission, organisations such as child advocacy group Bravehearts are preparing to ''triage'' the information they receive before it reaches the commission to make sure it is useful and to support those coming forward.