A bitter political stoush has erupted as workers on the West Gate Tunnel downed tools on Wednesday after the Liberals and the Greens united in state parliament to halt the $6.7 billion project.

Backed by the Nationals, the parties used their superior upper house numbers to scuttle the approval for the project in the upper house in a 22-18 vote.

While the state government has lashed out at the Liberal opposition for standing in the way of the project, it focussed its attack primarily on the Greens.

Roads minister Luke Donnellen said the “reckless parliamentary manoeuvre” halted construction work, threatened jobs and and threw into doubt promised truck bans on some Yarraville and Footscray routes.

But newly installed western suburbs upper house Greens representative Huong Truong hit back, arguing that the new toll road faces strong community opposition, would make traffic worse and entrench car dependence.

“This is a once in a generation opportunity to reshape the transport system across the western suburbs,” she said.

“We need to listen to the experts, who overwhelmingly want more public transport and less giant toll roads.”

Labor seized on a growing schism between The Greens and the Maribyrnong Truck Action Group, which backs the project in principle but is demanding tunnel filtration and wider truck bans.

Mr Donnellen highlighted a statement by MTAG that it is “bitterly disappointed” at the Greens –  a long time ally – helping block parliamentary planning approvals for the West Gate Tunnel Project.

“Unfortunately this is just another chapter in the bizarre and unhelpful politicisation of the infrastructure needed to take trucks off residential streets in Melbourne’s inner west,” the MTAG statement stated.

“We were never naïve enough to think that The Greens would support a major new freeway for Melbourne. However they did support previous government plans for a truck bypass with on/off ramps that would create a more direct route for trucks to the Port of Melbourne from the West Gate Freeway.”

Ms Truong said The Greens supported the West Gate Distributor plan – new ramps linking the West Gate Freeway with the Port of Melbourne – so the government now has an opportunity to go back and build the project they took to the last election.

“We stand resolutely with the community on eliminating congestion and truck pollution, but the solution isn’t another private toll road which will hand billions of dollars to Transurban.”

Mr Luke Donnellen said moves are underway to start again on the project as early as Thursday.

A statement by Transurban to the Australian Stock Exchange noted planning approvals may take the form of a Planning Scheme Amendment or “an alternative approval pathway”.

Transurban chief executive Scott Charlton said more than 800 people already employed on the project.

“After nearly three years of planning, development and public consultation, we have an agreement with the State to build the West Gate Tunnel Project and are committed to providing Melbourne with this desperately needed infrastructure as soon as possible.”