The Lachlan River reached major flood level in the central-west town on Friday, with access to its business centre cut off.
Some 2200 Forbes residents and 250 homes had been affected in the flooding, according to the State Emergency Service.
NSW SES southern zone commander Benjamin Pickup said the flood focus was on the Lachlan River and the Murrumbidgee River near Wagga Wagga, with residents told to get ready to evacuate at nearby Narrandera and other low-lying areas.
"We also continue to see major flood warnings across the Murray River with those significant rainfall events they had in Victoria yesterday and the day before, and that will be an area of focus going through to next week," he told ABC TV.
There were 63 flood warnings in place across NSW on Saturday morning, nine of which were at emergency level.
The SES performed seven flood rescues across the state in the past 24 hours and it received 213 calls for help.
A let-up in the rain has been forecast for most of NSW in the coming days, although the Bureau of Meteorology says renewed flooding is possible for parts of the central west and southwest.
More rain is expected to lash towns such as Gundagai, east of Wagga Wagga, from mid-next week.
Warnings for renewed flooding from recent rainfall are also current for the Belubula, Gwydir and Macquarie Rivers.
Significant falls in northern Victoria will continue to affect the Murray River, leading to possible minor flooding in Albury and other NSW towns near the southern border.
Mr Pickup said it was possible rivers would rise rapidly even if the weather was fine due to the significant rainfall across western NSW over the past few weeks.
"The (flooding) will continue to move downstream, so we encourage residents to be aware of the conditions and monitor if they live near a watercourse," he said.
BOM senior meteorologist Jonathan How said heavy rain cleared overnight but many areas had seen very high falls in recent weeks.
He said parts of southern and central NSW had set October rainfall records, including at Broken Hill in the state's far west.
"Catchments are very, very wet and rivers have responded very, very quickly, and these rivers are expected to remain high for at least a few weeks," he told ABC TV.
Mr How said forecasters were watching another weather system, which could bring further rain to the east coast by the following weekend and lead to further river rises.
30°C