An initial project budget of $2.6million for replacing Hinahina bridge, near Owaka, has been increased to $3.4million.
The NZ Transport Agency will pay $2million (59%) and Clutha District Council the remainder.
Council service delivery group manager Jules Witt said Clutha's additional share of $320,000 would be funded from depreciation and would not have an effect on rates.
The increase was to meet minimum NZTA bridge specification requirements and account for ``uncertainties''.
The 110m bridge, which crosses the Catlins River and links Owaka and Jacks Bay, was brought to the council's attention during long-term planning in 2015, after its dilapidated state began causing nearby residents concern.
After extended investigations, the council proposed last year to replace rather than repair the bridge, to reduce overall long-term costs, given maintenance expectations.
Tenders for the project would open late in January, and a contract would be awarded in March.
Construction is expected to take about 14 months.
