More rain is hitting swollen creeks and catchments in inland NSW as a search continues for two men missing in floodwaters.

Multiple river systems across the state are in flood, with 95 warnings active and 10 evacuation orders in place.

The State Emergency Service undertook 39 flood rescues in the 24 hours to Wednesday morning while efforts have resumed to locate the two men missing in the Southern Tablelands.

The pair were riding in the back of a ute swept off the road while being driven across a spilling causeway about 50km from Boorowa on Monday night.

Police say two others in the cab were able to free themselves and get to safety.

In the Riverina, more rain is expected as the Murrumbidgee River rises and Burrinjuck Dam spills, causing major flooding at Gundagai where levels similar to the April 1989 flood are possible on Wednesday.

It’s the town’s fourth major flood in as many months but authorities say low-lying caravan zones, parks and sportsgrounds are most likely to be impacted as most homes have been built on the surrounding hills.

Moderate flooding is also likely downstream at Wagga Wagga in the afternoon.

Further along the Murrumbidgee, major flooding continues at Hay and moderate inundation at Narrandera, with major flooding possible early next week.

Major flooding is expected along the Lachlan River at Nanami and Forbes, where an event similar to one last experienced in June 1952 is possible from Friday.

Further downstream, major flooding continues at Jemalong, Condobolin, Euabalong and Hillston.

The Bureau of Meteorology also expects major flooding on the Bogan River at Nyngan, Mulgawarrina and Gongolgon.

Flooding is also likely for one of the state’s largest regional centres after the Murray-Darling Basin Authority increased its releases of water from Hume Dam in response to continued rain on Monday night.

Combined with inflows from the Kiewa River downstream of the dam, the Murray River is expected to approach or exceed major flood level at Albury.

As of Tuesday, the dam was 96 per cent full.

Evacuation orders are in place for residents in Moama and Mathoura on the Murray, at Cowra in the state’s central west and Tumut, in the foothills of the Snowy Mountains.

– AAP