Flood emergency still 'a long way to run'

South Australia's Murray flood emergency still has a "long way to run" despite the peak making its way through the river system and water levels starting to fall.

The state government has extended an emergency declaration until early March which gives authorities extra power to control activity on the river and direct support agencies.

Environment and Water Minister Susan Close said the flooding remained a concern and the recovery would be a major endeavour.

"We have a long way to run," she told reporters on Tuesday.

"We are going to be switching increasingly into the recovery phase.

"If people have a house or property that has been affected there will be free initial assessment done and then there will be funding to support people to be able to clean that up.

"We will manage that, we will organise that and we will work with the community."

With restrictions on recreational activities on the Murray remaining in place, Ms Close said safety was still the key issue.

"We don't want them to last a day longer than they need to," she said.

"But making sure people are safe is the overwhelming priority."

The Murray flooding is shaping up as one of the most significant natural disasters in the state's history, especially in terms of its economic impact.

Initial forecasts suggested about 4000 properties would be flooded to some degree, including about 400 primary residences.

Work by the State Emergency Service over the next few days should provide more clarity on the number of homes impacted.

The flood peak has moved through the length of the Murray in SA, reaching the Lower Lakes late last week.

Water levels across the system have fallen, in some cases considerably, or are at least stable.

Water flows across the border are expected to fall to about 60 gigalitres a day by mid-February, down from a high of about 190 GL around Christmas.

The bulk of the state's levee system has so far held up, including those protecting major assets such as the one at Renmark built near the local hospital and another at Mannum protecting businesses on the main street.

There have been 68 catastrophic levee failures and 168 major problems but most have been with structures protecting agricultural lands.

The flooding has also closed about 120 roads across river communities with most of the state's ferry services also shut.

Of the 13 Murray ferries only those at Narrung, Cadell, Tailem Bend and Waikerie are still operating.