A police spokeswoman said police were investigating a solo vehicle crash, reported at 3.38am last Saturday, which had damaged a pole in the area.
The car driver had later sought treatment at Dunedin Hospital but was understood to be not seriously injured.
A later visitor to the site said a pillar at the bridge had been twisted on its plinth and a section of cast iron guard rail on the decorative wrought iron fence had been fractured.
Mr Saunders said the structure of the bridge over the Water of Leith, at the north end of George St, had itself not been damaged.
"But there is significant damage to the wall on the northern upstream side of the bridge.
"Most of the stone and concrete blocks have been dislodged and the upstream guardrail was also displaced.
The bridge was a "well-known local landmark and one of the earliest bridges of its type in New Zealand", he said.
The council had sought heritage advice on the bridge repairs and would "reinstate the existing blocks and guardrail as much as possible".
Repair work was expected to start in the next couple of weeks and to be finished in a couple of months. The cost of the repairs had "not been determined at this stage", he added.
