Shareholders' interests would be placed above those of the Illawarra community if Port Kembla and Port Botany were leased to the same private operator, South Coast Labour Council secretary Arthur Rorris said yesterday.
The union leader was responding to statements by Minister for the Illawarra Greg Pearce in a budget estimates committee meeting this week.
Mr Pearce told the committee it would be "quite desirable" to lease both ports to the same owner "because it will allow the management of an interconnection of the two ports and obviously it will allow for additional infrastructure spending and capital spending to be programmed for both ports".
Mr Rorris said the ports were already owned by the same entity: "the people of NSW".
He said leasing the ports to the same operator would create a monopoly focused on money.
"Once you start selling to a private concern the number one consideration, by corporations law, is the profitability of its shareholders," Mr Rorris said.
"If that profitability is increased by favouring one port over another whilst holding a monopoly over both, then that is what they will do.
"Their key consideration will not be the interests of the people of the Illawarra, it'll be their profitability and their hold over that market."
Yesterday Mr Pearce said his comments did not mean the government would look more favourably on a bidder who wanted both ports.
"While having one operator for both is not essential, it may have potential to streamline the management of the two ports and given the growth in trade and freight, may give an operator a significant incentive to grow the business. Equally a lease to separate operators could also be beneficial.
"We welcome bids from all interested parties - bids will be considered on the basis of what will enhance existing port operations and deliver the most benefits and opportunities to the region and NSW.
"The Port Kembla transaction, which will be based on a 99-year lease, is due to be completed in the first half of 2013."
Mr Pearce also said $100 million that would go to the Illawarra from the leasing of Port Kembla had not been earmarked for any particular project.
"We do not want to make decisions based on electoral matters as other governments have done; we want to make sure that the decisions actually are the best in terms of the overall development for the community," he said.