A section of road was closed near the Marne St intersection from July 22 and surveying and rock removal had been continuing along a 50m stretch of cliff since then, a Dunedin City Council spokesman said.
Last week’s weather resulted in some delays.
"While a significant amount of rock has already been removed, we have unfortunately also found more unstable rock above the road than expected, meaning the work will take longer," the spokesman said.
Work was expected to continue for the rest of this week, at least, he said.
"It is possible we may be able to reopen one lane of the affected section of Portobello Rd sooner if all goes well.
"We apologise for the inconvenience, but it’s important to make sure the road is safe for everyone to use."
Contractors had been on site almost every day since July 22, he said. A detour remained in place at Doon St "and we’re asking residents living there to park their vehicles off the street, if possible, for now".
The Peninsula Connection shared path was still open.
"We will stop cyclists and other path users when rocks are being removed and let them through when it is safe to do so."
Adjustments were made to bus services.
"When the closure was first announced, we cancelled some evening services to facilitate work in the area, and cancelled a morning run when we moved to operating vans," Otago Regional Council transport manager Doug Rodgers said.
"Initially, we operated smaller vehicles on the route to facilitate the tight turns required on the detour."
Mr Rodgers said this was challenging for passengers, as the smaller vehicles did not have features such as bike racks and wheelchair access.
Options were reassessed and a modified route from Doon St allowed the regular-sized buses to be used again.
Some parking restrictions have been brought in to ensure buses have enough room.
