PORTLAND, Maine — After a sixth workshop last week on a much-debated proposal for a high-rise housing and retail complex in Bayside, the Portland Planning Board appears ready to decide the project’s fate.

The board is tentatively scheduled to conduct a final public hearing on the Midtown complex plans on Dec. 10, and then will vote whether to approve a site plan and subdivision plan for the project.

The Midtown proposal calls for phased construction of four 15-story towers on 3.25 acres of former scrap yards along Somerset Street. The complex would include 700 market-rate apartments, two parking garages with a total capacity of about 1,100 vehicles, and more than 95,000 square feet of retail space.

As the board prepares to make its decision, opponents and proponents of Midtown are turning up the volume in the debate.

A group of residents recently mounted an aggressive campaign to stop the project and similar large-scale commercial development.

“There are massive problems with [Midtown], and there are minute problems,” said Peter Monro, co-founder of the group Keep Portland Livable. “But the more people know about this project, the less they like it.”

The group claims Midtown will alter Portland’s skyline, create fierce winds and shadows, and obstruct access to the neighboring Bayside Trail. The group also objects to zoning exceptions and tax breaks provided to the developer, The Federated Cos.

“People say that Bayside is a special case, and any development is better than no development there. The problem with that argument is that other developers are hearing that and are going to want the same sorts of things,” Monro said.

Greg Shinberg, the local consultant representing Federated, said he understands the concerns, but a project of Midtown’s size can’t please everyone.

“Every project has its good parts and its bad parts. And we understand there are differences of opinion about what a beautiful building is,” he said. “But it’s not that we don’t listen [to the project’s critics]. The process has gone slowly, so that their good ideas could be implemented.”

Shinberg said Midtown may create some minimal wind and shadow effects, but that such effects are unavoidable near a large building. And Midtown’s size is driven by the economics of the project — such as the cost of driving pilings 100 feet through ground that is mostly landfill.

“You need density to make the infrastructure work. Otherwise, the numbers just aren’t there,” he said. “Is it driven by economics? Of course, it is.”

As for critics who have claimed the city is rushing the project to appease the developer, Shinberg said, “I don’t get it. This has been a very transparent project, a very thorough process. … But stalling this project now will not kill it.”