Paedophiles' criminal history will be revealed to juries more frequently under law changes set to be introduced by the Victorian government.

Prosecutors currently must convince a judge why a defendant's previous sexual abuse convictions should be part of evidence, but the change puts the onus on the defence to demonstrate why they shouldn't be.

The proposed change, one of the key recommendations of the child abuse royal commission, weakens the test to introduce what’s called tendency evidence in criminal trials.

Tendency evidence can include prior convictions or allegations of previous deviant behaviour and prosecutors use it to show a jury that a defendant has a propensity for that behaviour.

Prosecutors presently bear the burden of proving the value of the evidence substantially outweighs the prejudice to the accused.