The South Australian government has closed the River Murray to all non-essential activity, effective immediately, with the Premier saying the ban will be in place "for some time to come".
Swimming, boating, as well as motorised and manual watercraft are now banned between the New South Wales-Victoria border and Wellington, except for people working, visiting their own properties, making essential deliveries, or responding to emergencies.
SA Premier Peter Malinauskas said it was a difficult decision.
"We're approaching the peak, there is a lot more water that will be coming down the river over the course of the next seven days than what is currently the case — we had to draw a line in the sand on this," Mr Malinauskas said.
"When people are at risk, and our emergency services have to respond, that's a drain on those resources that could otherwise be deployed out in the community."
He said it would allow more flexibility on the issue of power disconnections, which has frustrated locals in the region.
Previously, an exclusion zone of 50 metres was in place around powerlines which Mr Malinauskas said had meant some disconnections had been avoided.
"By having a total ban of activity on the river, that will allow South Australian Power Networks in conjunction with the Office of the Technical Regulator to have a bit more flexibility ... to prevent those disconnections," Mr Malinauskas said.
He also said it would better protect levees in place across the region.
"We know that unnecessary wave actions up against levee banks can do them damage over time, and that's not a risk worth running — so in places like Renmark, in places like Mannum we need those levee banks to perform as designed," he said.
Tourism encouraged despite ban
Despite the banning of river activities, Peter Malinauskas said people could and should still visit the region to support local communities in need.
"Normally, at this time of year we'd want the river to be full of activity from recreational users and tourist operators and otherwise, so it is a regrettable decision," he said.
"You can enjoy the water without being on the water.
"There are hospitality service providers who would love the patronage and we still encourage people to go, but just follow the guidance and the advice.
"We will seek to reopen the river as soon as we can."
Deputy SA Police Commissioner Linda Williams said officers would continue to monitor the river, with a four-knot limit remaining in place for those still able to use it.
"If people still ignore those guidance activities that we'll perform, there is up to a $10,000 fine," Deputy Commissioner Williams said.
"We will also be using our air assets up and down the river to ensure safety and we will have a very highly-visible police presence along with marine safety teams."
Flood watch and act message issued
A flood watch and act message has been issued for low-lying areas of Gurra Gurra.
The SES has said there is a high risk of flooding for those areas and has urged people to prepare to evacuate.
