Police will lay additional charges against former union boss Kathy Jackson in the coming weeks, as she fights 70 theft and deception offences, a Melbourne court has been told.

The one-time union corruption whistleblower is accused of misappropriating more than $480,000 from the Health Services Union from 2003 to 2011.

Police allege she spent $100,000 of the money on travel, including trips to Hong Kong and Los Angeles and a stay at the luxury Bellagio hotel in Las Vegas.

Jackson appeared in the Melbourne Magistrates Court via video link from New South Wales, where she is living while on bail.

Prosecutors told the short hearing they were planning to file additional charges against Jackson in the coming weeks.

Jackson said she was concerned by the prospect, as prosecutors had previously told her there would not be any new charges.

But Magistrate Charlie Rozencwajg told her it was a matter to raise with her lawyers.

Jackson will return to court for another hearing in June before she faces a four-week committal hearing in November.