A historic Queens community with utopian principles at its roots is engaged in a battle over historic preservation.

A large group of residents in Sunnyside Gardens is pushing for the 1920s planned development to receive landmark designation from the city, an action the Landmarks Preservation Commission will vote to consider tomorrow.

The designation movement has cast a cloud over the relic of prewar urban planning efforts, as many neighbors are adamantly opposed because new restrictions would be imposed. While residents say the overall community atmosphere remains civil, the issue has grabbed the attention of the neighborhood, and tensions between the two sides have risen in recent months.

The 600-building neighborhood, with its towering trees and greenery-lined streets, seems almost out of place just three miles from Midtown Manhattan. Originally built with affordability in mind, the modest two- and three-story brick buildings have been recently selling for more than $600,000.

“It is one of the most important housing complexes — one of the most important examples of urban housing in the United States,” a resident involved with the movement for landmark status, Jeffrey Kroessler, said. As the LPC comes closer to tackling the issue, recent community meetings have been tense, Mr. Kroessler added, marred by interruptions and infighting.

Sunnyside Gardens was one of America’s first planned “garden city” communities, where green space and community cohesion were top priorities.

Initial regulations prohibiting development in the community expired in the 1960s, and numerous residents added fences to their back yards, among other modifications, until 1974, when the city put in place a designation that prohibited many alterations.

The existing protected status goes far enough, landmark designation opponents say, rejecting the notion that the community needs another layer of regulation in attempting to preserve the neighborhood’s character.

“We have to distinguish her between uniformity and a dress code — I’m for a dress code,” a resident who opposes designation, Ira Greenberg, said.

The LPC could unnecessarily require residents to use expensive materials, such as slate for roof repairs, while some might not be able to afford it, Mr. Greenberg said. “I think what we really need to preserve is the relationship between the buildings and the open space,” not intricate detail on buildings facades, he said.

By letting the LPC decide the issue, Mr. Greenberg added, the community would not be able to give sufficient input, whereas tackling the matter through zoning changes would be more democratic.

Proponents of the designation charge that the community needs different regulation, as the existing rules are poorly enforced and allow for alterations such as new windows and adding stucco.

A resident of the neighborhood for more than 40 years, Marguerite Bessant, said major alterations done without building permits are common, resulting in complaints and infighting among neighbors.

Standing in her backyard, Ms. Bessant pointed around the courtyard to various illegal alterations that she said could have been prevented with the protections of the LPC.

“It’s changing the structure of the neighborhood,” she said, “and we’re trying to keep the uniqueness of it.”