Dunedin City Council roading projects engineer Michael Harrison told the Otago Peninsula Community Board last week construction on the long-awaited project would start after Christmas, with work expected to be completed by the end of April.
The 220m wall will be part of repairing damage caused by a landslip at Turnbulls Bay in last year's June storm, which resulted in delays and inconvenience for residents.
Earlier this year, the council estimated the project - of which the New Zealand Transport Agency pays two-thirds and the council a third - would cost between $750,000 and $900,000.
Asked by the Otago Daily Times why the cost of the project, being undertaken by Downer, had increased so much, Mr Harrison said there had not been any large changes in the scope of the project.
''Over that time, the market has changed and there is a greater realisation about the costs of some of these works.
''The preliminary estimates were considerably lower than what it ended up being,'' he said.
The work included slip repair, preventive maintenance and widening the existing road to include a shared path for cyclists and pedestrians.
The wall would be an average of 4m high, but up to 7m in parts.
He accepted it had ''taken a while'' to get the project under way, but this was not unheard of for such complex jobs.
Community board chairwoman Christine Garey said it was a ''huge bonus'' the work included road widening, which was not originally scheduled for this section of road.
''So a crisis has actually turned into a positive,'' she said.
It was not ideal the project was being undertaken over the holiday period when the road was at its busiest, but she was happy it was finally happening.
''The community has been very patient and we've been very frustrated, as a board, at the delay.''
