Tony Woodhams told The Cornishman that while £5 million of the required funding has not yet been secured, the tendering process would give the scheme "cost certainty".
"We will go out to building companies and say this is the market we want to build," he said.
"The tendering process will take us through until March and building will probably start then."
Newlyn's Harbour Commission will pay £2 million towards the scheme.
The shortfall is expected to be met by the European Regional Development Fund and European Fisheries Fund.
Construction of Newlyn's new fish market, which was expected to begin this autumn, is an 18-month project incorporating a new market hall, an auction theatre and a meeting room.
The two-storey building will be situated four metres from the edge of Mary Williams Pier. Mr Woodhams said he was currently putting together a business case for the European Regional Development Agency.
He anticipates that funding would be secured "this side of Christmas".
"We had a meeting with Defra and the Regional Development Agency and others on Monday to look at any problems with funding and there does not appear to be any but that does not mean we've got a clear road ahead," he said.
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