$51.6 million in flood support announced as South Australia braces for crisis

South Australia Premier Peter Malinauskas has unveiled a $51.6 million support package as the state braces for its own flood crisis.

Malinauskas said evacuations and power outages were to be expected in the state's Riverlands region.

He warned that river levels would potentially remain high until autumn 2023.

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"We have got a journey ahead of us," he said.

Treasurer Stephen Mullighan said grants of up to $50,000 will be available to private operators who want to install their own levees and flood protection.

Households that have to evacuate will be eligible for $1000 per family, with a further $1000 to try to meet the first two weeks of new accommodation.

Those who don't have insurance will get $2000 for single people and $5000 for families, if they have to leave home.

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Sole traders will have access to a $10,000 grant if they are forced to close, while businesses with employees can get up to $20,000.

Households looking to buy a generator to combat power loss could apply for $500, while a business seeking the same is eligible for up to $4000.

Mullighan said there would also be a $3 million fund for primary industries.

Millions are also being spent on the state government's own flood-fighting, including levee construction and sandbags.

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Malinauskas warned there will be "thousands" of people who lose power in the state's burgeoning flood emergency.

He said parts of the power network would be disconnected in advance of the rising water levels for safety reasons.

He said there was still a lot of work to be done to minimise the impact, including ensuring businesses had adequate advance warning.

"Safety has to be the paramount consideration," he said.