Many tourists are still stranded, either camping in isolated areas or at remote roadhouses after more than 100mm of rain in recent days.

A large section of the Sturt Highway which links South Australia to the Northern Territory remains cut.

South Australian authorities said on Tuesday the highway between Glendambo and Coober Pedy was closed because of water still over the road.

The remote towns of Roxby Downs, Woomera and Andamooka are connected again after urgent repairs were carried out on the Olympic Dam Highway.

The Sturt Highway has since reopened between Port Augusta and Pimba but remains closed further north.

Travellers have been urged to avoid outback gravel and dirt roads for at least the next week because of flooding.

The SA Department of Infrastructure and Transport is issuing updates on road conditions.

The rail link between South Australia to the Northern Territory and even Perth have been hit as well with rail washouts.

"Due to a slow-moving rain event in South Australia, parts of the Australian Rail Track Corporation network between Adelaide and Tarcoola were flooded and operations have ceased," a spokesman said.

"Repair works are underway.

"Services between Adelaide and Perth and Adelaide and Darwin have been impacted. An estimated time for return to service is yet to be determined," the spokesman said.

"ARTC will provide regular updates on operations as information becomes available."

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The closure of the rail and road access to the NT is expected to cause freight delays.

Major supermarkets have been contacted for comment.

Falls of more than 150mm have been recorded in some places in the outback after an upper level low pressure system developed in the Bight between South Australia and Western Australia.

The weather system drew down tropical moisture from northern Australia.

The biggest totals over the past week were - Winter Springs 228.4mm, Kimba 200.8mm, Mt Ive 181mm and Buckleboo 177.6mm.

The Bureau of Meteorology said severe thunderstorms with heavy rainfall are expected to continue this week.

"Flooding is impacting multiple roads and towns so make sure you check the status of road closures before travelling in these areas," a bureau spokesman said.