Rail repairs could take weeks after outback flooding, Stuart Highway remains closed

A section of track between Spencer Junction in Port Augusta and Tarcoola. (Supplied: ARTC)

Work to repair washed out rail tracks that connect South Australia to Perth and Darwin could take weeks, leaving freight to be shifted by trucks.

However, the main highway from Adelaide to Darwin also remains closed between Glendambo and Coober Pedy, forcing drivers to detour through Queensland, after what has been described as a "one-in-200-year" weather event.

Outback flooding over the past week has caused major damage along part of the rail line between Coondambo and Lyons, 473 kilometres north-west of Port Augusta.

That section of track is used by freight trains that are travelling between South Australia and Western Australia, and between South Australia  and the Northern Territory.

"Services from Adelaide to Perth and Darwin continue to be impacted," rail owner Australian Rail Track Corporation (ARTC) said.

Repair work is ongoing, and could take at least 12 days. (Supplied: Australian Rail Track Corporation)

The company said up to eight areas between Adelaide and Tarcoola were "still inaccessible due to flood waters".

"We've had what meteorologists have described as a one-in-200 or one-in-300-year weather event, which has significantly damaged our network," company spokesperson Anthony Meere said.

"We've seen rivers flooding where they shouldn't flood and track washed away as a result of the flooding incident.

Parts of South Australia received record-breaking rainfall totals over the weekend.

The company said the line was expected to remain closed for at least 12 days — but that further storms this weekend could push that back again.

"Our estimated time, at this stage, is anywhere between 12 and 17 days to be able to get freight services back up and running," Mr Meere said.

"There is the potential those falls will impact our efforts to be able to get the track up and running as quickly as possible, within that 12-to-17-day range."

Several sections of rail track were washed out by heavy rain. (Supplied: Australian Rail Track Corporation)

Water levels are slowly receding along the Stuart Highway, the main road connecting South Australia with the Northern Territory, but the 250-kilometre stretch from Glendambo to Coober Pedy remains closed.

Dozens of vehicles have been left stranded, and road freight to the Northern Territory is now being diverted through Queensland.

The Eyre Highway between South Australia and Western Australia remains open.

Western Roads Federation's chief executive, Cam Dumesny, said freight that would typically be moved by rail was now being moved by road at a time the trucking industry was "critically short of drivers".

"About 80 per cent of WA's land freight from the eastern states comes by rail," he said.

Trucks are stranded as they wait for floodwaters to recede on the Stuart Highway. (Supplied: Mat Kerin)