Advice from the Otago Regional Council includes strong indications resource consent would be needed, or at least it "strongly encourages" pre-application discussions.
That is not what the city council has decided to seek, potentially setting up either a standoff or a challenging road ahead to gain approval for groyne reconstruction.
Instead,
city councillors voted 9-5 last week to seek a certificate of compliance, which might enable the city council to get around a costly consenting process.
It is hoped a timber groyne might help build up the beach and a trial has been proposed by Dunedin Mayor Jules Radich.
Seeking the certificate appears to rely on remnants of a groyne being considered an existing structure, and that is disputed.
The city council has been told "there is no structure to replace or reconstruct", as groynes no longer existed.
Consent for a new structure would be required, as well as a consent for the associated disturbance and occupation of the coastal marine area, the regional council’s consents team said.
"Any proposal to reinstate groynes at Ocean Beach would require careful assessment of their effect and effectiveness in line with the provisions of the Resource Management Act."
Advice from a consents planner to Mr Radich a year ago was the structure’s occupation of the common marine and coastal area was "not currently consented" and "a coastal permit would be required for new groynes under discretionary activity rules".
Mr Radich has been adamant remnants of the groyne amount to an existing structure, which should be repaired.
In a statement issued last week, the city council said the estimated cost of reconstructing a single groyne was between $180,000 and $320,000, depending on materials used, and consenting costs could range between $15,000 and $250,000.
A confidential staff report, now partly released to the Otago Daily Times, said operating costs could be up to $110,000 a year.
Construction costs were consistently estimated at $320,000 and, within the material now released, there was no mention of a cheaper figure.
Cost estimates were based on a drawing supplied in 1919, materials, site management and reinstatement work.
It was assumed in the report hardwood timber would be shipped in from Australia.
However, it has sometimes been suggested old poles from Aurora Energy could be redeployed and this might save on costs.
Maintenance repairs were estimated at $50,000 a year and the remaining $60,000 of operating costs were put down to monitoring.
"Any monitoring programme would need to assess the effectiveness of the structure and whether the groyne is having a positive or negative impact on the coast.
"Allowance has been made for aerial surveys, CoastSnap data analysis and bathymetry surveys."
Council staff said proceeding with groyne reinstatement could have budgetary impacts for existing work programmes.
