A deluge which has swamped the dead heart of Australia and left towns and properties isolated has set new rainfall records.

In the outback town of Birdsville, in far western Queensland, Senior Constable Scott Gander pored over rain records dating back to 1892 in an effort to give the downpour, which began on Saturday night, some historical perspective.

It eclipsed anything he found.

In the 24 hours to 9.00am, 168 millimetres fell in Birdsville - the average annual rainfall delivered in one day.

Since Saturday the town has registered more than 225 millimetres - nearly nine inches on the old scale.

And the deluge, which came across the Simpson Desert from the Northern Territory with a slow moving monsoonal system, continues to bring rain to Central Australia.

Huge falls of more than 150 millimetres have been recorded all around Birdsville - 300 kilometres to the north, 100 kilometres to the south and just as far to the east.

The outback water courses that run through the arid centre towards Lake Eyre - the Georgina and the Diamantina Rivers, and Eyre Creek - are rising rapidly.

Last year flooding rains in the north around Mount Isa sent the water down those waterways all the way to Lake Eyre. It may happen again.

Birdsville is awash and the main road out of town, which crosses the Diamantina River, is covered in floodwaters. It could be weeks before the road is reopened.

The weather system is now moving to the south-east where it is dumping more rain on the channel country of south-west Queensland, adding extra water to Cooper Creek.

It has been in flood since heavy rain in western Queensland late last year.

The tiny settlement of Innamincka, in outback South Australia, has been isolated since late January when the Cooper spread its banks to cover the causeway into town.

Some supplies have been ferried in by aircraft but the strip is now too wet to use.

The 13 people in town are just sitting it out. The biggest problem they face is that they are running short of diesel fuel.

The weather system is forecast to track further east across southern Queensland and northern New South Wales.

If it delivers heavy falls, there it could bring the biggest run in the rivers at the top of the Murray Darling basin since the drought took hold a decade ago.