Dozens of cars lined up this morning for the reopening of a major West Australian highway, after record flooding in the Kimberley left people stranded and a regional town only accessible by air.

The Great Northern Highway connects the towns of Broome and Derby in WA's north west, but heavy rainfall due to ex-Tropical Cyclone Ellie caused extensive damage to the critical transport route in January.

A 10-kilometre section of the road close to Willare suffered some of the worst damage with 3km completely washed away, leaving Derby inaccessible by road over the recent week.

A construction crew of about 40 people has established a temporary single-lane gravel track for vehicle access, but this will only be accessible during daylight hours. 

Main Roads Operations Director Peter Sewell has been overseeing the temporary fix and he said the damage could not have been predicted. 

"You cannot design to accommodate that."

Road is critical to the town

Many Kimberley residents need the road for essential services and supplies, while Derby has relied on freight being delivered by air and barge since the start of the year.

Shire of Derby West Kimberley president Geoff Haerewa said he hoped the reopening would take some pressure off the outback town. 

"It's been tough," he said. 

With the wet season still far from over, Mr Haerewa said locals were anxious about the prospect of more rain. 

"We've always got one eye on the sky, looking out for any rain that could come," he said. 

"We're just hoping the road stays open as long as possible."

Derby resident and business owner Heidi Sampey said she hoped the reopening would bring some stability for locals. 

"There is so much that normal people take for granted, but now we can access those things again."