Queensland’s government is defending a plan to increase road tolls for truck drivers to pay for a $450 million motorway upgrade.
The state government says Transurban wants to upgrade the congested Logan Motorway, including building a number of new entry and exit points.
Treasurer Curtis Pitt says Transurban will fund the project by increasing truck tolls on its Logan and Gateway Motorways, meaning government funds will not be used.
The Transport Workers Union says the announcement is "at best half-baked and at worst policy on the run, and a knee jerk reaction" to the pressure the government faces on infrastructure delivery.
"We have significant concerns regarding this announcement that yet again more economic pressure is placed on truck drivers to keep their wheels turning to make ends meet," state branch secretary Peter Biagini said in a statement.
But Mr Pitt said it was impossible for the government to fund every infrastructure project across Queensland out of state funds alone.
"We must partner with the private sector, we must look at different funding models that allow that to happen," Mr Pitt said.
Main Roads Minister Mark Bailey said road use by commercial vehicles had risen 52 per cent, compared to just seven per cent by private vehicles, between 2010-2014.
"This project promises to deliver a safer and more efficient motorway network by relieving local traffic congestion, reducing travel times, while improving safety and enhancing connectivity with other major road networks," he said.
The government expects to receive Transurban's final proposal in late 2016 and it will then decide whether to proceed with the proposal, modify it, or consider other options.