Two weeks of delays are expected at the Deborah overbridge on State Highway 1 south of Oamaru as work on the highway takes place later this month.
The highway under the railway overbridge would be reduced to one lane with traffic control from September 21 to September 28, a New Zealand Transport Agency spokeswoman said.
At one stage, SH1 traffic would be kept away from the work site and diverted on to a 5 to 10 minute detour on Whiterocks and Weston Rds, from 9am to 4pm each day.
Outside of those hours the highway would revert to having one lane open with traffic control in place.
''If drivers could be aware that that's [the detour] not the main highway, that would be really good. Just a bit of care [needed],'' the spokeswoman said.
Routine repairs were required after drainage issues and ponding damaged theroad during the winter, she said.
