Rowers who skim the bay near the Sydney Fish Market are mounting a push for bolstered water safety measures before construction starts on the waterfront site's multimillion-dollar revamp.

The Berejiklian government revealed last year the cost to taxpayers of its ambition to overhaul the fish market on Blackwattle Bay at Pyrmont had ballooned by half a billion dollars to $750 million.

An artist's impression of the new Sydney Fish Market building at the head of Blackwattle Bay. Credit:NSW government

Submissions on the government's plans to bulldoze the existing fish market before constructing the new building nearby show boaters and rowers fear the project will disrupt their activities, shorten the bay's existing rowing course and increase the risk of collisions between vessels on the water.

One of the groups that uses the bay is Burwood's MLC School. In its submission, the school's Rowing Parent Support Group supported the project but held "some concerns about the construction and development process".