Attempts to replace fuel excise revenue with another tax to accommodate the rise of electric vehicles have all but stopped with officials asked to design a national road user charge warning the lack of progress is threatening to create a budget black hole.

People involved in planning the new charge, commissioned by Treasurer Jim Chalmers in December 2023, said discussions had stalled within months. One official, who asked for anonymity to speak freely, said cooperation between federal and states governments slowed after the announcement of new car emission standards in March.