The bridge over the Clutha River was strengthened a year ago.
The project cost $770,000 and involved fixing steel plates to the 21 beams.
Work began this week on repairing the deck and bearings at the south end of the bridge.
The need to repair the bearings was uncovered during the bridge strengthening project, NZ Transport Agency Otago Senior Network Manager John Jarvis said.
The cost of the project was about $180,000 and it would take about a fortnight, he said.
As well as repairs, the bridge was also being cleaned of pigeon droppings, a regular maintenance activity, and as the paintwork was corroded by the bird droppings, it would be retouched and the trusses painted.
None of the work was related to recent damage to the bridge caused by a car crash.
This has damaged a cross-member but has not affected the bridge's structural integrity and a plan for that repair was still being worked through, Mr Jarvis said.
No costs for that repair had been estimated at this stage and the driver of the car or their insurance company would also be contacted.
