That means the one-lane State Highway 8A bridge across the Clutha River will be closed between 9am and 5pm on Thursday to allow inspections and work to go ahead.
Waka Kotahi NZ Transport Agency will create a 32km detour through Hawea Flat for people travelling between Tarras and Wanaka or to the West Coast.
It will make arrangements to accommodate school buses and emergency vehicles at short notice.
Essential maintenance work was done on the 100-year-old structure late last year.
Running boards were replaced, the handrail was repaired and abseilers tightened deck bolts.
WKNZTA senior network manager Robert Choveaux said bitumen sealing patches would be applied to the deck and new signs would be put up.
Aspiring Highways is the contractor doing the work.
The detour will use Camphill Bridge. It is not approved for certain types of heavy transport vehicles, so drivers of those will need to take an alternative route or wait to use the Red Bridge outside the closure times.
