A former Melbourne childcare worker facing more than 70 child abuse offences has been charged with another 83 alleged crimes including six counts of child rape.

Joshua Dale Brown, 27, was arrested in May with police alleging he abused eight children - including a five-month-old - between April 2022 and January 2023.

The case prompted authorities in July to urge about 2,000 children across more than 20 centres where Mr Brown had worked to undergo testing for infectious diseases.

On Thursday, police said the new charges relate to alleged offences against four new victims between 2019 and February this year at three centres as well as extra offences against the initial eight children.

The families of the four new victims have been notified, police said, and the new charges do not involve any new childcare centres so health authorities are not recommending any further testing for infectious diseases.