A proposal to build a mix of residential and commercial condominium units along Ocean Street will be the subject of a public hearing on April 25.

The developer, Leddy Hauser Associates, will present to the Planning Board a plan for Mill Cove Landing, a three-story building containing 27 residential and four commercial condominiums. It would replace Ocean Street Auto Center, a long-standing auto repair business. The proposal would run along Ocean Street from D to E streets.

City officials, neighbors and civic leaders have informally commented favorably on the plan, but a strong objection has been raised over possible long-term effects of a zoning change being requested.

Nick Burnett of 3 D St. wrote in an e-mail sent throughout the neighborhood that he and his wife “think that these developers will build an attractive and high quality condominium, but, we are fearful that the zone they seek will not only destroy the contiguous neighborhood of small homes …but it would set a precedent encouraging other developers to seek such zoning changes.”

Burnett calls for “conditional zoning or some such variance,” rather than a zone extension to protect the neighborhood’s residential character.

The zone change being sought by the developer would change the eastern half of the parcel, bounded by Mill Cove, from village residential to village commercial. This change would be necessary for the project to comply with density specifications. The western half, which extends 150 feet from the center of Ocean Street, is zoned village commercial.

The concern is that an extension of village commercial zoning would make it legal for tall mixed-use buildings to intrude into the residential neighborhood, regardless of the fact that Leddy Hauser does not plan to build on this portion.

A similar concern surfaced last month when Mill Cove Landing was presented to the City Council at a workshop. The question was raised as to what might happen to the tract if for some unforeseen reason Leddy Hauser was unable to carry out the project after the zone was changed.

At that meeting, Leddy Hauser Principals Paul Leddy and Peter Hauser agreed with City Planning Director Tex Haeuser to provide the desired neighborhood protection via a deed restriction.

Haeuser said conditional zoning, where a special zone is established with its own set of rules is a tool “we use very sparingly. ” Haeuser said that was because conditional zoning tends to confuse the nature of an established zone with pockets of differing permitted uses. For cases like Mill Cove Landings, he said, correcting potential problems with deed restrictions would be the better course.

“I certainly do not like to see zoning changed to accommodate a single project, but a change here, with the protection of a deed restriction, is preferable to conditional zoning,” said Rommey Brown, chair of a civic committee that developed the recently adopted city’s vision for Knightville/Mill Creek.

Mill Cove Landing, she said, “would fill the missing tooth for the Ocean Street vision.” Brown noted that the developer has modified the plan since it was first presented to the neighborhood and to the City Council, in deference to the neighbors.

The changes included the elimination of a boardwalk along the tidal Mill Cove shoreline, and stepping down the building heights along C and D streets to minimize the scale adjacent to existing homes.

After the Planning Board makes its recommendations, the project will go back to the City Council for action.

The public hearing on the proposal will be held in the South Portland City Council chambers on April 25 at 6:30 p.m.