Recent releases had reduced the dam level to 94 per cent at the start of the week, but this week's rain event is predicted to deliver 200 billion litres - 200 gigalitres - into the storage.

Inflows peaked at 80 to 90GL per day on Wednesday, and were easing to about 55GL on Thursday.

Releases - which had dropped to 3GL per day to allow for the predicted inflows into downstream tributaries - have been increased to 22GL a day in response.

Manager of system operations Adrian Langdon said ongoing release targets had been discussed with the local airspace advisory panel.

Those earlier releases had created capacity to capture and hold 70GL of inflow, allowing time for large tributary flows downstream of the dam to peak and move downriver before higher dam releases resumed.

The rain of the past few days was at the upper end of the forecasts, and it was anticipated the storage will reach 100 per cent Wednesday night.

"Even with inflows peaking at up to 90GL/day, having 70GL of airspace capacity has allowed us to keep releases at just over 20GL/day, greatly reducing potential downstream flow peaks," Mr Langdon said.

The Lachlan River is predicted to reach minor flood levels at the Iron Bridge in Forbes on Sunday and moderate flood levels at Jemalong on Monday.