The signature project of Victorian Premier Daniel Andrews, the Suburban Rail Loop, is expected to blow out to $200 billion, four times the initial estimates, and dwarfing the state’s total predicted debt of $167 billion.

Mr Andrews in 2018 said the three-stage rail loop project, which will connect Werribee, in Melbourne’s south-west, to Cheltenham, in the city’s south-east, would cost $50 billion.