Wagga Beach was entirely underwater and a sheltered barbecue area were flooded on Tuesday morning after the river reached 5.38 metres overnight.

The water level cut off the Wiradjuri Trail between Wagga Beach and Charles Sturt University's Riverina Playhouse.

WaterNSW is releasing more water from Burrinjuck Dam to increase storage capacity to capture more rain forecast by the Bureau of Meteorology for the weekend.

WaterNSW system operations executive manager Adrian Langdon said the storage levels, the BOM forecast and wet catchments have required WaterNSW to continue releasing water between rain events.

"While there is no cause for alarm, we are monitoring the situation carefully. We work very closely with the bureau so we have access to the nation's best weather forecasting," he said.

"As dam managers we never want to exacerbate a flood-prone river system downstream of the dam by adding water to any existing, naturally occurring tributary flows. During the weekend rain event we saw significant uncontrolled tributary flow downstream into the Murrumbidgee and Tumut rivers, and we cut our dam releases back to minimum until those tributary flows had peaked."

Burrinjuck Dam is at 99 per cent capacity having received 67,000 megalitres of inflows since July 15.

WaterNSW will release 15,000 megalitres from Burrinjuck today following on from 10,000 megalitres yesterday and is also considering releases from Blowering Dam.

"This will be our management strategy while the storages remain high and the BOM forecast of ongoing rain events in the months ahead remains current," Mr Langdon said.

"We are also in close contact with downstream stakeholders to ensure we are receiving community feedback and making decisions that factor-in downstream impacts."