A sewage pipe broken by a driller working for Opus and Powerco will take weeks to fix.
The pipe, a main interceptor, is under Karoro Rd, near the Beach Rd intersection.
A Whanganui District Council spokeswoman said a driller working for Opus and Powerco broke the pipe.
She said the pipe is seven metres deep "so it is a big job that is likely to take weeks, not days, to fix."
There are no health issues for residents, she said.
A Whanganui resident contacted the Chronicle and said they thought Talley's had broken the pipe "drilling test holes"
However the council spokeswoman said this was not the case.
The shared pathway along the stopbanks between Balgownie Ave and Beach Rd has also been closed as a precautionary measure for public safety.
Signs have been put up at the entrance of the walkway advising people to use Heads Rd. The area around the damage has been cordoned and road closure signs have been put up at Beach Rd.