A $900,000 redecking project last year was stalled when council officers examined the Oamaru Harbour landmark's structural integrity and found the suspect piles to be more than 75% deteriorated.
"We had plans to do the next stage of the redecking - we checked the structure and, obviously, it needed quite a bit of work," she said.
The budget for the redecking work had been carried forward and a portion would be used for the remedial work.
The maritime construction specialists were expected to be able to stabilise 10 piles a week, Mrs Julius said.
Bay Underwater Services owner Rob Campbell was born in Oamaru and though the historic wharf was "decrepit" in places, working in Oamaru was a plus.
"I am stoked to get back here to do a bit of work in my own hometown," Mr Campbell said.
While a diver inspected the work site yesterday, Mr Campbell kept in contact with him via a two-way underwater radio.
A Bay Underwater Services engineer would inspect the casings today and cement would be poured to encase the piles on Monday, Mr Campbell said.
And though hydraulically driven underwater chainsaws and the like were not typically found in the average toolshed, the work was the same, he said.
"It's just building underwater."