Belfast Harbour's new chairman has said growing and improving the already profitable business will boost the argument for not selling off the key port to private investors.
David Dobbin said further development of the port and surrounding estate - viewed as one of Northern Ireland's most valuable assets - would likely suffer following a sale.
It comes after the Belfast Telegraph revealed that discussions were ongoing over selling off the harbour - estimated to be worth around £400m.
It is Northern Ireland's primary business gateway, accounting for around three-quarters of sea trade here.
"The downside of a sale would be a lower rate of port development and the upside would be cash for the Executive," said Mr Dobbin, who is also head of United Dairy Farmers.
"Our job is to show the long term of the Harbour... once it's sold, that is it.
"The rate in which it would invest back in to the harbour would slow if there was a sale - that has to be weighed against the sale.
"We want to ensure politicians understand the pros and cons - we want to work with them, but the better job we do, the stronger the argument for keeping the port. It's very much up to the Executive to decide to what to do, whether they want a sale."
But he said it was "business as usual" for the harbour.
"We don't want to get distracted on whether the Executive will put it (the harbour) up for sale," he said.
Mr Dobbin also predicts that Belfast Harbour will witness its biggest growth in prime office space and an increasing number of tourists going through the port during this year.
But exports could suffer in 2015 due to a strengthening pound against the euro.
"There is strong demand, areas in the pipeline and inward investment," he said.
"Importing and exporting will depend on the general economy - some will pick up.
"It's going to be on a sector-by-sector basis. The food sector in part will be under more pressure, for example.
"We are continuing to invest in all areas, including tourism and cruise ships - making Belfast the port of choice going forward."
Last month, Regional Development Minister Danny Kennedy said he would be appointing a panel to assess options over the harbour's future options.
Ukip's David McNarry has said that there is already "serious consideration" being given to selling off the harbour estate to private buyers.
More than 23m tonnes passed through the port hub in 2014, - with business witnessing an upsurge of 1.6% last year.
That was record growth for the business, buoyed by a boost in cruise ship passengers, consumer goods and exports.
The entire estate also includes a number of well-known businesses, such as George Best Belfast City Airport, Harland & Wolff, and Titanic Belfast.
Belfast Harbour is now investing £140m in a number of projects over the next few years, including cruise ship, cargo and crane facilities, as well as the second phase of its City Quays development.