The WA Road Transport Association has called for greater investment in the state's supply routes, as the region's roads continue to suffer the effects of recent flood events. 

The Kimberley region has experienced one of its largest wet seasons, with flooding events from the Goldfields down to the Great Southern washing away roads and bridges. Repair bills from the damage are expected to run into the tens of millions of dollars.

WA Road Transport Association executive officer Cam Dumesny told the ABC the deluge had worsened 'already unkempt roads'.

"Our roads, particularly the Great Eastern Highway, were already in a tragic state," he said.

"This water would just exacerbate this situation."

In June last year, the Auditor General found WA had an $845 million road maintenance backlog.

Dumesny told the ABC the audit figure exposed that the major supply routes across WA were not being looked after.

"We need to take it seriously. We have a supply chain or a logistic system in this state that has worked really well, but the problem is we have milked it fairly heavily," he said.

"We have produced 40% of our export income from the regions. If this is your most profitable machine you need to look after it.

"We produce 70% of Australia's gold, yet we are the second highest-cost gold producer in the world — one of the key drivers for that is our transport and logistics costs.

"The freight sector to our economy is critical and it is often unrecognised. We need a WA approach to strategic freight planning."