Dunedin City Council projects engineer Evan Matheson said the area had taken a battering during violent gales that struck the city on May 12, driving waves over newly-constructed sections of seawall along Portobello Rd.
The waves stripped plantings and backfill from behind the seawall near Macandrew Bay between Company Bay and Glenfalloch and lofted rocks, wood, plastic and other debris across the cycleway.
Two weeks on, the partially-completed, $35.5 million project yesterday remained in a battered state when the Otago Daily Times visited, with cyclists opting to take to the road rather than risk punctures on the cycleway.
Mr Matheson said it was expected initial repairs would be carried out within days, "if not immediately".
However, further work was needed over the next six months to better protect exposed sections of the seawall and cycleway from powerful waves at several headlands, he said.
That could include placing objects in the water in front of the seawall, to disperse the power of waves and prevent splashing over the top, he said.
The wave action at high tide, or when southwest winds prevailed, had affected grass growth and caused soil erosion in places, he said.
Mr Matheson said council staff had been mulling over improvements to the problem sections before this month's storm.
Ice plants replaced grass along the water's edge in some places, with partial success, but soil erosion had continued, he said.
The May 12 storm had stripped away many of the new plantings, as well as exposing previously buried plastic sheeting, he said.
The plastic - which ran down the back of the seawall - prevented fill material used as part of the road-widening work from leaking out through the seawall and into the harbour, he said.
"It looks very unsightly, but it's fixable. It's one of the many things we have to deal to after this storm event, unfortunately."
Repairs would be "straightforward" and cost less than $10,000, with the work covered by an existing maintenance contract, Mr Matheson said.
He had no concerns about the quality of the workmanship.
"I don't know if anything would have stopped that [storm]. It was quite an extreme event. Yes, we've probably had more damage than we might reasonably expect. We just have to deal with that; get all the debris off the path for a start, and then reinstate the grass and any plantings.
"The quality of work is fine. It's just in a perfect world we'd probably have a seawall that's a whole lot higher."
Asked if that was a design flaw, Mr Matheson said that was "a bit harsh".
"It was a design detail that we need to review in places," he said.
"We are certainly aware that we had a problem before the storm event, and the storm event has made it a whole lot worse in a very short space of time.
"We have to get our thinking caps on about what is the best long-term solution," Mr Matheson said.
