The EV rebates in NSW were not covered by legislation, so it would be very easy to stop them.
Well the NSW Electric Vehicles (Revenue Arrangements) Act 2021 No 25, was introduced by the former government and supported by the now current government. This law defines the Road Usage Charge that will apply to EVs In NSW from 1 July 2027 or when BEVs are 30% of new vehicle sales, whichever occurs first.
To introduce a “new EV“ tax would require a new law or amendment of the existing one. I can’t see that happening. Unless of course the High Court rules that an RUC is in fact an Excise.