He expects to vacate the West Quay offices by year's end for new second-level offices looking down the Inner Harbour towards the Iron Pot and East Pier.
Construction of the new two-storey coolstore and office block to adjoin the current factory started last month.
It is intended that the coolstore will be available for the ling fishing season, which will start next month.
The building was designed by Strata Group and built by Gemco Construction.
The project, including the offices, is expected to be complete in November, at a cost of about $3 million.
A key feature was the upstairs views which Mr D'Esposito said would be important to the business's overseas clients, some of whom visited several times a year.
Some had been with him since 1983 when he opened Harbour Inn Seafoods on the old Gear Meat Co site in Petone.
Brother and fellow director Joe D'Esposito said the company had developed across the industry as a quota owner, vessel operator, processor, wholesaler, exporter and retailer.
It has three "shops", from the on-site frontage many customers still referred to as Snapper Jack's - despite the name being dropped when the site was purchased - to a shop in Heretaunga St, Hastings. It now has an online business employing at least five staff.
The company has almost a century of fishing heritage in New Zealand, dating to the arrival of grandfather Antonino Muollo and three brothers in 1917, from the Italian seaside village of Marina di Puolo. Members of the family in the village are also still involved in the fishing industry.
Also involved in the current business are Nino's sons Marcus, the general manager, and Daniel, who runs the Hastings shop.
The biggest of the company's vessels is the 31m automated long-liner Pacific Explorer, which fishes solely out of the Chatham Islands.
Napier is its closest mainland port.
