Hundreds of tourists were stranded in Alice Springs after the desert town was deluged with rain at the weekend.

And with more rain forecast for coming days, "the process could repeat itself", the Bureau of Meteorology has warned.

The usually bone-dry Todd River flowed for the second time in a week as the red heart of Australia was hit with hundreds of millimetres of rain.

About 40mm fell on Alice Springs alone, and Northern Territory police on Monday urged motorists to remain cautious on the roads.

Palm Valley, south-west of Alice, recorded the highest reading with 116mm.

Saturday's downpour stranded 22 people in a flood about 50 kilometres west of Alice Springs.

The group of four-wheel-drive motorists and children spent the night in their cars west of Jay Creek.

There are unconfirmed reports that a four-wheel-drive and a ute were swept from the road by the current, but no one was injured.

Police were able to drive out on Sunday when the waters subsided.

Day trippers visiting the Glenn Helen Resort, at the western end of the West MacDonnell Ranges, were also stranded by the flood.

Almost 100 people bunked down at the resort over the weekend, and manager Colin O'Brien said most were still there on Monday morning.

He recorded 47mm of rain on Saturday, topped up by another 25mm on Sunday.

"We've had a full motel here over the weekend," Mr O'Brien said.

"A few people with pressing commitments went back yesterday, when the road was still closed, but most of them stayed on and left this morning.

"There is a lot of debris on the road - rocks, sand, mud - lots of rubbish."

Mr O'Brien said the outback, which hadn't had any decent rain since January, looked like it had been "burnt with a giant blow torch".

"It was just that dry. There was lots of dead bushes, everything looked dead," he said.

"We needed a good rain and now maybe we'll get some wildflowers ... this should make a big difference to the look of the country."

The heavy rains forced police to block off all causeways around Alice Springs over the weekend and the road south of the Stuart Highway was closed to small vehicles.

Police said large vehicles could proceed at their own peril.

Several roads remain closed today, including the Tanami Highway, Maryvale Road, Santa Theresa Road and Namatjira Drive.

Police warned that drivers who travel on closed roads may be prosecuted under the Roads Control Act.

Mark Hentschel, from Darwin's Bureau of Meteorology, said more rain was on the way.

"We expect more rain today and for tomorrow, with the potential for large amounts of rain," he said.

"It will certainly ease by midweek, but I wouldn't go so far as to promise it will clear.

"Then, later in the week, we could see the whole process repeat again."

He said the average rainfall at Alice Springs Airport for the month of November was only 53.1mm.

AAP