One block of Whanganui's Somme Pde will be completely closed to traffic for six weeks while fresh slumping at a dropout is repaired.
One edge of the road started to sag toward the Whanganui River after the June 2015 flood. Whitakers Civil Engineering was contracted to design and construct the repair.
It has closed one lane of the road and controlled the other with lights during the repair process, which was to have finished on June 30.
The dropout repair has been "a right pain", Aramoho resident Fiona Donne said.
People could get around it by using Bute and Perham Places. But access for essential services such as ambulances has been delayed.
"The detour is not that much quicker than waiting for a green light."
Buses have been unable to keep to timetable, and Mrs Donne sat in one and watched as a big funeral procession held up other traffic for 20 minutes. She's hoping the repair won't take too long.
Then, a few weeks ago, "movement in the lower foundation of a portion of the repair" stopped work while the company's geotechnical and design engineers looked for a solution.
They have found one, and work resumed on Tuesday, with lights still controlling traffic.
The solution to the slumping means a short length of Somme Pde will have to be closed from July 27 until September 15, the company said.
Residents whose properties are directly affected will be contacted before the closure. During it traffic will detour along Cumbrae Place, Perham Place and Roberts Ave.
Whitaker Civil Engineering took on seven design and build contracts in the district in 2016. The other six have been completed. They are bridges in Tokomaru West, Koatanui, Longacre, Heao, Matthews and Kainui Rds.