Kati Thanda-Lake Eyre, which covers about 9500 square kilometres when full, could receive falls of 100mm to 300mm by next Tuesday or Wednesday.
The lake, which usually fills with water from its north-eastern tributaries, may even record rare inflows from its southern ones.
The weather system has also caused flooding in parts of Queensland and Western Australia.
Forecasters caution computer models have been jumping around regarding the precise rainfall intensity, locations and times.
But residents in Central Australia are being urged to monitor forecasters and look out for flood warnings.
