The Bloomberg administration is showing a new interest in promoting industry on the waterfront, marking what port advocates call a notable shift from the city’s emphasis on reclaiming the shores of the five boroughs with condominiums and parkland.

In coming weeks, the city’s Economic Development Corporation plans to release a study that recommends building up the local maritime support industry, calling for a significant expansion of ship repair facilities along the waterfronts. The report comes as the city is expanding industrial ports in Sunset Park and Staten Island, warming to the idea of constructing a freight rail tunnel between New Jersey and Brooklyn, and scaling back its plans for large-scale development at a series of piers in Red Hook, leaving in place a container port.

Groups and business owners involved in marine-related activities say the city’s actions suggest that the Bloomberg administration may be approaching the waterfronts in a different way for a variety of reasons.

While city officials deny the policy has shifted, the city’s actions come as booming global and local economies have increased dramatically the amount of cargo coming into the city, and many of the administration’s largest residential waterfront development initiatives have already been approved.

“We all learn as we go,” the manager of the Brooklyn-based Erie Basin Barge Port, Robert Hughes, said, referring to the Bloomberg administration. “I think maybe as time has gone along, they’re realizing the importance of the maritime industry to the city.”

The Bloomberg administration also has faced a constant push to focus more on maritime- and freight-related issues from Rep. Jerrold Nadler, who said he welcomed the changing tone.

“They’re warming to maritime uses — I definitely feel that,” Mr. Nadler said.

More than anything else, the rapid growth in the marine and shipping industry is fueling the need for more maritime services, Mr. Nadler said, a growth that is only expected to continue as the city’s population swells.

According to numbers provided by the city, the volume of containers coming into New York Harbor increased 51% between 2001 and 2006. More ships means more repairs, and a draft of the city’s maritime support study, obtained by The New York Sun, suggested that in the next nine years, the city could need more than eight new land-intensive dry docks for large ships, known as graving docks.

“The growth has been dramatic,” the president of the Economic Development Corporation, Robert Lieber, said.

With the increased traffic comes a growing need for support services, Mr. Lieber said, as the city looks to parts of Brooklyn, Staten Island, and the South Bronx to establish some of the repair facilities.

Still, Mr. Lieber said the emphasis on the maritime support helps to spur job creation outside Manhattan and is consistent with previous actions of the administration.

“The one thing I think we’re trying to do in this administration is diversify the economy,” he said.

However advocates of the rival use for the waterfront — residential real estate development — caution that preserving industry that can often locate elsewhere can come at a cost.

“It may be fine in the interim to select some very limited locations where industrial waterfront uses would be appropriate,” a developer who is involved in multiple waterfront projects, Henry Wollman said. “On the whole, the great need in the city is still housing.”