Traffic was delayed for more than an hour in Balclutha yesterday after a tractor hit the side of the bridge.
Balclutha Fire Brigade Senior Station Officer Stu Powell said the tyre of a tractor ''just nicked'' the side of the bridge which ruptured a line in the vehicle and caused hydraulic fluid to spill on to the road.
Firefighters were called to deal with the incident about noon yesterday.
A section of the bridge was closed off and firefighters diverted traffic which caused a build-up along Clyde and Essex Sts for more than an hour.
Traffic also built up along the Kaitangata highway.
The bridge remained blocked off until gravel could be poured over the spill, Mr Powell said.