PORTLAND – A major development along the waterfront in Maine’s largest city is moving closer toward getting under way.

Riverwalk LLC and Portland officials have completed negotiations that could lead to a development that includes a parking garage, luxury condominiums and retail space worth at least $45 million.

The parking garage, which would have more than 1,100 spaces, is the centerpiece of a plan that would launch the redevelopment of a neighborhood near the planned Ocean Gateway cruise-ship terminal. The goal is to finish the parking garage by the time Ocean Gateway is completed, likely in 2007.

“Once you provide the parking, redevelopment will occur very quickly and very strongly,” said City Councilor James Cloutier, chairman of the community development committee. “We anticipate other people coming forward with creative ideas and economic proposals that will be an asset to the city.”

Riverwalk, led by developer Drew Swenson and Shipyard Brewing Co. owner Fred Forsley, agreed to pay $850,000 for an acre of city-owned land where 78 residential condominiums would be built in three buildings.

Two of the condo buildings would be five stories tall and overlook the cruise-ship terminal. A six-story building would be built at Fore and Hancock streets.

In return for its multimillion-dollar investment, Riverwalk would receive a $5 million property-tax break over 12 years. Riverwalk’s proposal was chosen over three others in public bidding last year. City Council is expected to consider the deal next month.

Riverwalk’s development would generate an estimated $750,000 to $800,000 in yearly property taxes once it’s completed. The taxes would be reduced during the period of the tax break.

It is one of several proposed major developments.

Joseph Boulos, who owns the real estate firm CB Richard Ellis/The Boulos Co., has proposed a $245 million project with a 17-story office building and sports arena a few blocks away, next to Portland City Hall.

It would have a 10,000-seat arena as well as a 140,000-square-foot convention center.

Other buildings would include a 250-room hotel, a 300,000-square-foot office building and a parking garage with enough spaces for 1,700 cars.

The project’s future may rest ultimately with the Legislature if state financing becomes necessary.