The Premier has threatened to rethink Transurban's 10-year CityLink tolling extension deal in a dramatic escalation of the dispute over contaminated soil that has bogged down the government's West Gate Tunnel project.

It comes a day after the project's joint-venture builders - CPB Contractors and John Holland - gave an ultimatum to tolling giant Transurban: pay them more to deal with contaminated soil at the site of the major road project or they will tear up the contract and walk away.

Premier Daniel Andrews has warned the government would renegotiate Transurban's deal to toll drivers on CityLink for another 10 years given the "silly games" at play that are delaying the flagship road project.

Works already under way on the West Gate Tunnel in Yarraville. Credit:Meredith O'Shea

The Andrews government has the power to pass overarching legislation that changes or hinders CityLink tolling.