More properties along the Murray in South Australia have had electricity supplies cut as river levels rise with many more, even some not flooded, facing the same fate.
Thousands of shacks, homes and other buildings along the river may be inundated as forecasts for water flows continue to grow.
The state government says flows are now expected to hit at least 165 gigalitres a day from early December which would flood more than 300 properties.
There is a moderate chance of hitting 200 GL and a smaller chance of reaching 220 GL, which would likely impact more than 5000 properties including some farms and industrial premises.
That would also make it the biggest flood event since 1956 when flows across the border climbed to about 340 GL.
SA Power Networks said some low-lying properties had already had their power cut and it could be months before those services were restored.
But the company warned that as it became increasingly difficult to disconnect individual properties more widescale cuts would be required.
That could affect homes and other properties not necessarily at risk of flooding.
"We are not prepared to send our crews into floodwaters to undertake disconnections," Head of Corporate Affairs Paul Roberts said.
"That means we will be disconnecting electricity supply at points that are safe, likely impacting multiple customers."
"We are making daily assessments about the safety of electricity supply and we also are having to assess our ability to get crews safely to these areas."
With water levels continuing to rise, work is underway to repair and improve a series of levees protecting local towns as they face being seriously tested for the first time since the mid-1970s.
Most were built to withstand flows of up to 210 GL but now have some capacity to remain safe at higher levels.
However, plans are underway to relocate some hospital patients and aged care residents in low-lying areas as water levels rise.
Local infrastructure has also been hit, with some roads, walking trails and camping grounds already underwater.
Almost all houseboat operators on the river have shut down, with the faster-flowing water proving too dangerous while rising levels will soon close a number of ferry services across the Murray.