NZ Transport Agency Waka Kotahi (NZTA) said delays of up to 15 minutes could be expected at the Rangitata River Bridge due to piling works.
NZTA journey manager in South Canterbury Tresca Forrester said that intermittently over the work-day, traffic would be managed single-lane on the bridge using portable traffic lights.
The actual dates might change depending on water levels around the bridge piles.
Speed levels would also be reduced at the bridge while the work is under way, and outside of work hours, weekends and overnight to 70kmh.
"Traffic will be released as quickly as we can with crews aiming to minimise delays", Ms Forrester said.
The bridge had to be reduced to single-lane traffic when the crane boom was against, or close to, the bridge.
At other times, traffic would revert to two lanes.
When necessary, crews would clear queues, and emergency vehicles would be allowed across at short notice.
Electronic signs at Rolleston and Rakaia would warn drivers of the delays.
