An artist's impression of the Footscray Road elevated freeway section of the West Gate Tunnel. Credit:Victorian government The contract also leaves open the possibility of Transurban raising revenue through "other activities" approved by the government, which may include the state determining a share of net revenues. Despite criticisms the government released the contract while much of Victoria was in shutdown, Treasurer Tim Pallas said it was "setting new standards for transparency, releasing the West Gate Tunnel contracts and allowing Victorians to see for themselves the benefits this project will bring to our state". "Never in Victoria's history has so much information been made available about a major road project," he said. On Friday the Opposition wrote to Transurban warning "at the earliest available parliamentary opportunity" it would vote against the planning scheme amendment, which is required for the project to proceed.

The proposed West Gate Tunnel as it cross the Maribyrnong River. Credit: Victorian government "Given the expressed opposition of other parties in the Parliament of Victoria to the proposed WGT project, it would be prudent for Transurban to avoid any significant further expenditure on the proposed WGT project until the planning permission required for it has been considered by parliament." A government spokesman accused the opposition of "economic vandalism", saying there were no legitimate grounds to revoke the planning approvals. Illustration: Matt Golding "It's irresponsible, it's erratic, it's irrational," he said.

The Coalition holds 16 seats in the 40-seat upper house of parliament, while the Labor government has 14 and the Greens have five. The Greens have yet to decide how they will respond to the contract. But Western Metro MP Colleen Hartland said she was concerned the agreement's reference to "alternative approvals" would give the government a mechanism to bypass planning approvals in parliament. "If they're going to put that in the contract they should spell out exactly what that means," she said. Opposition transport spokesman David Davis, who led two successful attempts at revoking planning approvals in recent months, slammed the government for releasing the contract "under the cover of the Christmas New Year period". "This is a secret government," he said.

The former Coalition government refused to release the business case for the East West Link, yet Mr Davis slammed the Labor government's decision to redact "critical information" from the West Gate Tunnel contract. "The Coalition is very concerned about where this contract is heading." William McDougall, a transport engineer who told a Senate inquiry that the project was based on deliberately distorted data, is now calling on the government to release the document in "full form". "There are a lot of gaps ... that relate to key things like financial performance, and penalties under the KPI method of scoring performance," said Mr McDougall, who was originally hired by the Andrews government to assess the proposal. Premier Daniel Andrews announced two weeks ago that he had signed contracts with Transurban, with project costs escalating to $6.7 billion, up from last year's estimated $5.5 billion.

Work on the project is set to begin early next month, with a completion date set for 2022. The project will include a new tunnel under Yarraville and will widen the West Gate Freeway from eight to 12 lanes. It is designed to take 9000 trucks off local roads and reduce congestion on the West Gate Bridge, which the Western Distributor Authority predicts will be in almost total gridlock at peak times by 2031 if nothing is done. The government has indicated that legislation to operate the new road tunnel, and amendments to the CityLink concession, will be introduced into Parliament before the road is complete in 2022. It wants Parliament to approve a deal extending Transurban's lucrative 4.25 per cent annual increase in CityLink tolls for 10 more years, starting in 2019. This would also extend Transurban's tolling contract to 2045.

However, the Coalition and the Greens have flagged that they would block an extension of Transurban's CityLink contract in State Parliament's upper house. Mr Andrews has previously declared that Victorian taxpayers would foot the entire bill for the project if the Liberals and Greens followed through on threats to block the new tolling deal. Loading The government has argued that the cost blowout was due to the tunnels being twice as long as was planned in the original business case. A Transurban spokesperson said: "This project has been through the most rigorous consultation and development process ever seen for a new road in Victoria."