Former West Australian transport minister Dean Nalder admits it was "inappropriate" to start work on the contentious Perth Freight Link during the state election campaign.
It was reported that Main Roads set out two options for the then Liberal government, addressing the possibility of Labor winning the election and stopping construction.
One option minimised costs and delayed clearing at the environmentally-sensitive Beeliar Wetlands, but the former government opted instead to clear the wetlands at a cost of $50 million.
New WA Premier Mark McGowan on Thursday said he was furious the Barnett government chose the more expensive and environmentally destructive option to start the contentious project, knowing an election loss was likely.
The leaked document showed Main Roads set out two options for the then Liberal government, addressing the possibility of Labor winning the election and stopping construction.
One option minimised costs and delayed clearing at the Beeliar Wetlands, but the former government opted instead to cut a path through the environmentally- sensitive area, carrying the financial risk of $50 million in sunk costs for contract cancellation.
Sunk costs for the other option, which involved starting near Fiona Stanley Hospital in Murdoch, were half that figure.
Not only had Labor long vowed to tear up contracts, the Liberals knew polling was pointing to an election wipe-out.
Mr McGowan labelled the decision to start the project at the wetlands "grossly reckless and grossly irresponsible".
"They went for the far more destructive and expensive option - I'm very angry about that," he told 6PR radio on Thursday.
"They thought they were going to lose the election so they decided to burn the house down. That's cost the taxpayers of Western Australia tens of millions of dollars more."
Labor suspended work on the project within 24 hours of its landslide election win.
They thought they were going to lose the election so they decided to burn the house down. That's cost the taxpayers of Western Australia tens of millions of dollars more.
Mr McGowan told Mornings with Gareth Parker he expected to keep the cancellation cost at about $50 million.
Transport Minister Rita Saffioti later said the aim was to vary the contract, rather than cancel it, and assign the companies to other projects aimed at reducing traffic congestion in the metropolitan area.
"We want to have the opportunity to get our other projects built but also to keep the workforce employed," Ms Saffioti said.
"Of course, there's a cost of exiting the Roe 8 contract and the costs that have been incurred through the Roe 8 contract so far, and of course the cost of rehabilitation."
About 50 hectares need to be rehabilitated, she said, and the government would work with community groups that had already started helping by spreading mulch from trees that had been felled to make way for the road.