The middle section of the bridge was damaged on February 12, after metal flaps on a container carried on a wagon flew up, cutting access across the railway lines and meaning a longer walk for commuters who park near the harbour.
Dunedin City Council projects engineer Evan Matheson said the contract was worth $240,000.
The contract was to build the bridge "largely as it was", with a similar shape and similar dimensions to before it was damaged.
Mr Matheson said the company was salvaging what it could from the bridge and had ordered new steel from Singapore to replace what could not be re-used.
The replacement steel would be the same type as the steel that was damaged.
Transportation operations manager Mike Costelloe said he expected the bridge would be finished by late August or early September.
