Motorists travelling to St Arnaud could be delayed until the start of next week, after this week's heavy rains undermined a small bridge on Ararat-St Arnaud Road.
St Arnaud Sergeant Bill Alford said the water had created two holes on the side of the road surface across the bridge, just north of Gifford Road at Beazleys Bridge.
"One of those holes has undermined half of the northbound lane," he said.
"VicRoads has attended, and they are closing the northbound lane and putting in traffic control - lights and a 40 km/h speed limit. Engineers will look tomorrow at what needs to be done, they may have to dig up the road and if they do that they will have to divert traffic entirely."
Sergeant Alford said he didn't expect the problem to be resolved until after the weekend.