Major damage to the Oamaru Harbour breakwater, particularly from recent heavy seas, has prompted the Waitaki District Council to carry out urgent work.
Contractors have been asked to price the cost of repairs to about 60m of damage in the middle of the breakwater and work could start within the next few months.
Water services and waste manager Martin Pacey said the council had set aside money for work every two years and repairs were scheduled for next year.
However, because of the breakwater's age, the continuous impact of the sea and exposure, coastal environment preventive maintenance work, scheduled for next year, was needed now to repair areas where it had been undermined.
The cost of work was estimated at $200,000 to $250,000 and would be funded from depreciation.
It would involve replacing large rocks, smaller rocks and concrete on the seaward side, which protects the breakwater.
''Recent heavy seas have inflicted substantial damage on the breakwater resulting in urgent remedial work being required,'' he said.
The council usually saved up work on the breakwater because of the substantial cost of getting machinery and materials on site, with maintenance planned every two years.
The last major maintenance was in 2013.
Constructed in the 1880s, the breakwater was extended and raised in the 1930s and 1940s and had additional strengthening work done in the 1950-60s, most of which had now been lost by continual pounding of the sea.
The breakwater was a significant asset for a small local fishing industry and recreational users and had the potential to be developed for future eco and water-based tourism activities.
''To build a new, equivalent structure would cost anywhere from $24 million to $45 million so, even though considerable money is needed to do remedial work, it is far less than a complete replacement, which would be a heavy burden for ratepayers,'' Mr Pacey said.
