Far North Holdings general manager Chris Galbraith said the project had been split into two contracts, both awarded to Opua company Total Marine Services.
The first involved replacing the southern arm and would be completed by the first week of July in time for the Birdman Festival on July 6-8.
The second contract involved maintenance on the main walkway, including replacing structural piles.
Work was progressing well despite the weather, Mr Galbraith said.
"Obviously the inclement weather isn't ideal, but it's nothing of significance to the construction project."
The Birdman Festival involves contestants launching themselves from the end of the wharf in costumes and flying contraptions.