The Whanganui District Council has initiated legal proceedings to recover costs of more than $1 million to repair damage to a main sewer pipe.
The interceptor pipe at Karoro Road, off Beach Road, Castlecliff, was damaged in September last year when a contractor drilled through it.
In briefing papers presented to council's infrastructure and special projects committee on Wednesday it was stated that Powerco instructed Opus Consultants to undertake geotechnical investigations to support a foundation design for a new transformer at Powerco's substation at Karoro Road.
"Opus employed a contractor, Geotech Drilling Limited (GDL), to drill a bore at a potential site on Karoro Road to extract a core sample," the report said.
"In the process of drilling the bore, GDL damaged our interceptor pipe by drilling through the top and bottom of the pipe.
"At the position of the damage the pipe has a diameter of 1600 mm and is eight meters deep and under the Horizons stop bank. The repair of the pipe is estimated to cost more than $1.5M. WDC has initiated a legal process to determine who will be liable for the costs."
In a seperate report, also presented to Wednesday's committee, infrastructure manager Mark Hughes amends the cost of repair to $1.25 million.
"PowerCo has been very helpful over the incident. Divers have temporarily patched the damage, and a potential fix has been designed at an expected cost of $1.25m," Mr Hughes said in his report.
There were no health issues for residents, council said in an earlier report.
The shared pathway along the stopbanks between Balgownie Ave and Beach Rd was closed as a precautionary measure for public safety.
Signs were put up at the entrance of the walkway advising people to use Heads Rd.
The area around the damage was cordoned and road closure signs put up at Beach Rd.
In reponse to a question from deputy mayor Jenny Duncan Mr Hughes said the work was expected to be completed by the end of May.
Repairs had been delayed as a result of the weather event.