The government's High Productivity Freight Vehicle routes are useless for the trucks they are designed for, because bridges and culverts along the routes aren't up to scratch, according to the state opposition.
The oppositions Rural Roads, Ports and Freight spokeswoman Roma Britnell said the routes were announced with a great deal of fanfare.
But she said maps showed they were cut in half for the larger vehicles, because bridges can't handle the extra weight.
"The announcement was half baked and shrouded in spin," Ms Britnell said.
If the government wanted to make a real difference, bridges and culverts needed to be upgraded as a priority.
"You have to do the whole job - you can't just do half the work and then pat yourself on the back and say job done," Ms Britnell said.
"HPFVs are actually better for road surfaces, because they spread the weight evenly across the vehicle.
"Because they are larger, they carry more which means truck movements are reduced."
She called on the government to make it policy to upgrade bridges and give the Department of Transport the power to get on and upgrade them.
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Ms Britnell said bridge upgrades needed to start from the outside and work their way in towards ports.
"That way we make sure HPFVs can get to intermodal terminals where the freight can then be shuttled to the Port of Melbourne, via rail," Ms Britnell said.
"The government is finally making a start on the Port Rail Shuttle Program and the PoM is building its on dock-rail solution.
"But for this infrastructure to work to its full potential and to reduce truck movements across the entire state, we need to upgrade bridges to allow HPFV's able to travel to the intermodal hubs un-obstructed.
"Moving freight is like a jigsaw puzzle - you need all the pieces in place for it to work."