Contractors are making urgent repairs to the deck of the existing Kawarau Falls bridge.
The NZ Transport Agency said repairs to the wooden boards began on Tuesday evening and would be completed by tomorrow morning.
Their condition had ''deteriorated significantly'' over the past week.
The work was being carried out between 7pm and 6am, and would cause delays of up to 10 minutes.
The new $22 million two-lane bridge will not be completed until next March.
