Triple road trains, which are usually banned for freight transport between South Australia and Western Australia, will be allowed as an emergency measure to address supply-chain problems caused by a "one-in-200-year" weather event.
Record rainfall and flooding in South Australia in the past week have stopped trains carrying freight from the eastern states into Western Australia.
WA Transport Minister Rita Saffioti said trucks with three semi-trailers would be used to increase the amount of products moving by road and lessen the blow to supply chains.
"Triple road trains will increase the capacity of the trucks by about 50 per cent," she said.
"There [have been] safety concerns over triple road trains in the past, and that's why they haven't been allowed.
"But in this limited situation, they will be under escort going through parts of WA. That means there will be wardens with flashing lights to warn people."
Supermarket stock issues
Woolworths state general manager Karl Weber said most of its fresh produce was supplied locally and would not be affected, and warehouse stock would act as a buffer for other goods, but customers should only purchase what they needed.
"Customers may notice varying levels of availability of some products over the coming weeks," he said.
"As always, we ask customers to be mindful of others in the community and buy only what they need."
Workforce shortages created by COVID-19 have already caused supply-chain disruptions around the country, with poultry and meat supplies hit early this year.
Western Roads Federation CEO Cam Dumesny said the supply of processed foods to WA were most likely to be affected by the flood damage.
"Your pastas and those sorts of things, they're predominantly supplied from the east," he told ABC Radio Perth.
"The rail is washed out in about 18 places in South Australia. In some of those places, they've actually got to build roads to get in to fix where the rail's been washed out.
"The retailers have been working hard to get some of that now on the road. Inevitably, there will be some shortages. We're just going to have to accept that."
Alternative supply routes
Ms Saffioti said state and federal government had been discussing alternatives for bringing goods into the state.
"It is a massive logistical exercise: rail, road, maritime. And we've got the unions, we've got the logistic chains all in the same room," she said.
"It includes allowing triple road trains into Perth, and it also involves a potential land bridge, which means a combination of train, road, and train again.
The "land bridge" refers to supplementing disrupted rail lines with road freight.
Goods will be transported from the eastern states to South Australia by rail, shuttled by triple road trains to Kalgoorlie, then moved by rail again to Perth.
Ms Saffioti said the disruptions had shown the importance of expanding WA's freight and logistics infrastructure.
"This is an extraordinary event, but I think it highlights the need to further build resilience across Australia," she said.
"We're in discussion with the Commonwealth now about how we can have further options between the east and west."