South Australian Premier Peter Malinuakas says he understands the level of anxiety within Riverland communities over the "wall of water" heading down the Murray.
However, the premier remains confident everything is being done to ensure the region is as well-prepared as possible.
"There is absolutely a degree of caution and, in some instances, anxiety among community members on the ground," Mr Malinauskas told reporters on Friday.
"That's understandable because we've got a wall of water coming our way that we haven't seen in 50 years."
But the premier said many people were incredibly calm and well prepared and authorities were continuing to work on levees and other protective measures as well as provide support for those impacted.
His comments follow concern among some Renmark residents over how far the Murray will rise, apparantly prompted by water readings at the SA-Victoria border.
Mr Malinauskas said any confusion related to the difficulty in taking those water readings in the current circumstances.
"Ordinarily when those readings are taken, the width of the Murray is something between 150 and 200 metres wide. Now we're looking at a span of water that is six kilometres wide at that point," he said.
"We haven't seen an event like this in South Australia for over 50 years and that is bringing with it technical difficulties.
"From our perspective, the focus is very much on making sure that our preparations are at the appropriate level."
Up to 4000 properties in SA are forecast to be inundated by the water surging down the Murray, with more than 450 of those considered permanent residences.
The first peak in the river level is tipped to reach Renmark, near the Victorian border, about December 14.
The peak is expected to reach Mannum, east of Adelaide - where levee strengthening and construction efforts are in full swing - about December 27.
After a brief settling of water levels, a second and higher peak is forecast to reach the SA border towards the end of the year.
That could result in daily flows of up to 220 gigalitres.
So far more than 5000 properties across the region have been doorknocked to check on flood preparations, including 1100 that were still occupied.
People living in 647 of those properties had indicated they intended staying while about 290 households had asked for emergency accommodation.
The rising waters have prompted SA Power Networks to cut electricity supplies to 1850 properties with more disconnections likely.
The Lyrup, Mannum Upstream, Morgan and Swan Reach ferries are now closed, with the ferry at Walker Flat also expected to close.
The Waikerie ferry has moved to a higher landing.
The SA government has provided a $51.6 million assistance package, including support for tourism and other businesses, as well as direct emergency payments to homeowners.
This week it allocated an extra $1.2 million for emergency accommodation.
The federal government has provided a disaster recovery allowance to people across nine SA districts.
