A 26-year-old Melbourne childcare worker is facing 70 charges relating to eight pre-schoolers aged between five months and two years. 

Joshua Brown's worked across 20 centres since 2017 - and is accused of sexual assault and producing child abuse material.

The parents of 1200 children who'd been in his care have been advised to screen them for infectious diseases.

Australian correspondent Murray Olds says authorities are warning the parents to get their children tested - and treated.

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