Floodwaters on the Nullarbor are slowly starting to recede more than five weeks after drought-breaking rain cut off outback pastoral stations in one of Australia's most isolated regions.

Last month, more than 300 millimetres of rain was recorded in just a few days at various pastoral stations spread across the remote Nullarbor. 

The drought-breaking flooding closed the Trans Australian Railway Line for 21 days and briefly affected the Eyre Highway, which has had a flow-on effect on WA supermarket shelves. 

The Bureau of Meteorology's closest weather station, the Eyre Bird Observatory near Cocklebiddy, recorded 352.4mm of rain in March.  

That is 10 times the monthly average rainfall for March at Eyre, which typically received 30mm in the years between 1885 and 2024, with a 24-hour record of 141.2mm recorded on March 10. 

'Never seen water so high'

For pastoralists at ground zero, the flooding has been an unprecedented event.

Greg Campbell's family has been on the Nullarbor since the 1960s and he has never seen anything like it.

"We had some floods in 2010, I think it was, but it was nowhere near this extent, and we were only out of action for about a month before we could drive around," he said.

Mr Campbell operates a trucking business Nullarbor Transport Services.

A photograph taken this week of one of his cattle trucks stranded in waist-deep floodwaters at Kybo Station underlines the sheer volume of water still impacting the region.

"I've never seen the water up that high," he said.

"It has come down about a metre. It was up to the windscreen."

Mr Campbell said he was not aware of any cattle losses due to the flooding, saying the stock had made their way to higher ground and are now enjoying some "green feed" after six years of drought.

He expects the Trans Access Road, a gravel road which, as its name suggests, runs alongside the rail line heading east from Kalgoorlie-Boulder, to remain closed for an extended period.

It makes transporting in essential supplies an ongoing challenge.

"Now that the trains are up and running we can get some stores out on the train, and we're just starting to be able to drive around," he said.

"We can drive around the high area to get around the water, but we can't really access our roads.

"A lot of people have been trapped at their homestead because they can't drive anywhere."

Floods inundated homestead

Rawlinna Station, about 400 kilometres east of Kalgoorlie-Boulder, was arguably the hardest hit by the flooding with its homestead and workers' accommodation inundated by floodwater.

While water levels have dropped significantly, Australia's largest sheep station recorded another 3mm of rain on Sunday.

Gemma Chandler works alongside her husband Craig as an overseer at Rawlinna and they survived the peak of the floods living in a bus on higher ground.

She said the loss of the homestead, which was built in the 1960s when the station was established, was devastating. 

"The water's dropped over a metre and we've had three buildings now where we can see the floor and start the clean-up process," she said. 

When the couple arrived on the station two years ago with kayaks, people thought they were mad, but they were the main means of transport around the station.

She said her husband had used a kayak to tow a 24,000-litre diesel tank to higher ground to prevent a spill, among various other "incredible feats".

"Craig has done so many amazing things ... [like] floating generators out of the water using 44-gallon drums," she said. 

"The big generator was completely submerged but Craig got it running again."

The flooding prompted the postponement of the region's largest social event and annual fundraiser for the Royal Flying Doctor Service, this month's Nullarbor Muster at Rawlinna. 

Organisers on Tuesday announced new, tentative dates of June 28-30 for the muster, but warned it could be subject to change if road conditions were unsafe. 

"But at the same time it has done so much damage, so it is very bittersweet."