A Western Australia farmer has one message for motorists risking lives by driving through a heavily flooded section of the South Coast Highway next to his house: Don't.

Over the past few days, on little sleep, Wellstead local Steven Hall has been towing vehicles and their occupants from the flooded highway with his tractor.

"Before it got real deep I was using my LandCruiser with a snorkel, but I'm getting sick of it … getting water inside … so I'm dragging them out with a tractor," he said.

The south coast of WA has received heavy rainfall recently, with parts receiving up to 160mm in less than a week.

The section of the highway has about 1 metre of water across it and has been closed, with signage up, since Tuesday.

Mr Hall was perplexed as to why motorists were putting lives in danger by ignoring or moving the barrier to try to get across.

"It would be pretty hard to be unaware because they put up barriers [so that the] road is blocked off," he said.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 36 seconds 36 s Southern WA farmers battered by rain ( ABC Rural: Kit Mochan )

City 4WDs 'not made for it'

Mr Hall said about three cars had been completely written off after being pulled from the highway.

"These silly little city 4WDs, they're not proper 4WDs … they don't have snorkels, they're full of electrics … and as soon as they get wet all the electrics lock up," he said.

The section of highway has been closed since Tuesday and is under approximately 1m of water. ( Supplied: Steven Hall )

"The engine stops, they lock in park gear … so when I drag them out I just have to drag them out physically with the wheels locked.

"Their cars are basically destroyed by the time I get them out."

Aside from the burden of long nights spent being a good Samaritan, Mr Hall's tractor has not emerged unscathed.

"When this is over I'll have to drain all the oils out of the transmission … transfer cases … and put new oil in because it's gotten water in it," he said.

Mr Hall said the people he had been rescuing cars for were not Wellstead locals, and there was a mix of vehicles from sedans up to light trucks.

"It's tourists, it's people from Albany, it's people from Perth," he said.

Although Mr Hall empathised with drivers caught in the floodwater, he urged motorists to take the detour.

"Don't even go through it, go around. I'm even going to go that way when I go to Albany today," he said.

Unnecessary risks

Main Roads WA acting regional manager Brad Lenton said people needed to obey the signage.

"All vehicles are currently prevented from using that road," he said.

Main Roads WA have received reports of people removing barriers to drive through the closed section of the South Coast Highway. ( Supplied: Steven Hall )

"There are signs at both ends of the road closure, and barriers which should prevent vehicles from going through that section.

"We have also had reports of people removing the barriers to try and get through the floodwaters, but of course when the road is closed, that's final."

Mr Lenton praised the efforts of volunteers such as Mr Hall, but said the burden should not lie with him.

"We always appreciate the efforts of others to help out people in distress, but people are taking a risk by going through the road closure, which we certainly don't support," he said.

"We strongly advise anyone taking that action to stop doing it."

Mr Lenton said could be a week before a shorter detour was in place.

"Main Roads is currently looking at an option for light vehicles to use a shorter detour via Shearer Road and Mettler Road," he said.

The current detour is via Gnowangerup–Jerramungup Road and Chester Pass Road.