The South Australian government has declared a major emergency as River Murray floodwaters continue to rise, with the potential for a second peak "even higher than the first".
Modelling shows there will be a flood peak in early December, with the possibility of another peak in late December or early January.
SA Premier Peter Malinauskas said there would be increased impacts to communities, businesses, infrastructure and agriculture.
He said the current modelling for the river flow of 175 gigalitres per day had not changed, but the Environment Department had provided new information about the possibility of a second peak.
"What we have seen in recent days is yet more rainfall in the eastern seaboard in critical catchments areas, combined with a substantial release of water from the Hume Dam," he said.
"Those two things combined mean we now face a genuine possibility of another peak to the river flow.
"At the very least, we face the prospect of [an] elongated and protracted high-river-flow situation, which does elevate the degree of risk."
He said the second peak "could potentially be even higher than the first".
State cabinet will travel to the Riverland on Tuesday where it will announce a relief package.
Mr Malinauskas said the major emergency declaration would allow his government to be in the "best state of preparedness for the inevitable recovery effort".
He said it would also give Police Commissioner Grant Stevens additional powers to manage the rising river rises.
Mr Stevens said the major emergency declaration would come into effect on Monday and he would work to appoint an assistant State Coordinator for the recovery effort.
He said he could only call on the Australian Defence Force (ADF) when "we believe we have exhausted all local resources".
"They are ready sitting in the State Emergency Centre ready to receive requests when that time is appropriate," he said.
Volunteers working to bolster levees
State Emergency Service (SES) chief executive Chris Beattie said levee work to help protect towns along the river had been "progressing very well".
He said 11,500 sandbags were being distributed over the weekend from five different stations in the Riverland and 110 tonne of sand was being delivered to the community every day.
"It's important for homes and businesses to ensure their properties are well prepared for these flooding waters," he said.
While addressing concerns that Mannum locals were being subjected to sandbag limits, Mr Beattie said there were plenty available.
"The challenge with this flood event is it's not over in a night," he said.
"These waters are going to be raised and protracted for months to come, so a sandbag wall around a property is not going to protect that property for an extended period of time."
He said the SES was also working with councils to find new temporary levees to protect Mannum and Morgan, as well as Lake Bonney and Cobdogla.
"It's a long haul, we've got months of response to go with the river," he said.
