The Murray-Darling Basin Authority (MDBA) and Goulburn-Murray Water expect to commence works to reinstate the Mildura Weir next week.
MDBA Mildura Regional Manager Andrew Kremor said the lock would not be available for about a fortnight from Monday and there would be no pedestrian access around Lock Island and Lock Park.
"The weir was removed in July to avoid infrastructure damage and allow the increased flows from winter rains and runoff to pass through unhindered," Dr Kremor said.
"We are only now seeing the flow peak from the winter rain in the upper catchments, with almost 57,000 megalitres per day currently passing Mildura.
"Flows will recede and are expected to drop below 40,000 megalitres a day towards the end of next week, allowing reinstatement of the weir to start."
He said it would take about a week for GMW to reinstate the weir and rivercraft would not be able to access that section of the river until the work was done.
"The upstream level will fall around two metres during this time before returning to the normal pool level when the weir is installed," Dr Kremor said.
He said reinstating the weir would return the weir pool to its normal operating height and allow communities to resume usual activities.
"We thank the community for their patience while we complete these works," Dr Kremor said.
The Mildura Weir and Lock 11 are operated and maintained by Goulburn-Murray Water on behalf of the Murray-Darling Basin Authority.
