The Bloomberg administration is seeking zoning changes that would allow for substantial new development along much of 125th Street, a move that could transform a major Harlem thoroughfare into a dense hub of activity.

After avoiding the area for decades, developers are warming to the corridor as its retail market flourishes and nearby housing prices reach levels that 15 years ago would have seemed almost unfathomable. Aiming to leverage the soaring real estate market, the city wants to convert the historic corridor into a regional destination for business, retail, and the arts, allowing for an estimated 2,300 new apartments and more than 600,000 square feet of office and retail space in coming years. The plan, which goes before the local community boards in coming weeks, has drawn criticism from neighborhood residents, who say the dense development will not fit in with the character of the area. The real estate industry, while it supports the plan, is calling for more density around the Metro-North station on Park Avenue, consistent with the city’s goals of transit-oriented development.

The concept of new development is a relatively recent one for the expansive African American and Hispanic area that occupies much of northern Manhattan. Between the 1960s and 1980s, the region was hemorrhaging population as the city’s economy faltered, so much so that the city claims in planning documents that due to widespread foreclosures, it owned about 40% of the housing stock at one point.

The seemingly unstoppable real estate market of the past decade has shone a new light on the area, especially 125th Street, allowing for the arrival of national retailers such as Old Navy, and developments such as the planned Harlem Park, a glass 20-story office building just west of Park Avenue being developed by Vornado Realty Trust.

For the past four years, the city has been talking with the community and devising its rezoning plan for the corridor, which stretches between Frederick Douglass Boulevard and Second Avenue and 124th and 126th streets. Now, with the rezoning proposal at the start of the seven-month approval process, the Bloomberg administration is poised to open the area’s doors to considerable new development, particularly for office space and arts and entertainment uses.

“Folks want to build higher right now,” Assemblyman Keith Wright said. “You have some rather large vacant lots that are being held onto by private developers, and they’re just waiting for the proposed rezoning.”

The city’s plan would allow for more than double the existing density along the central section of 125th Street, with new buildings allowed to rise to 29 stories. With the aim of further enlivening the street life of the corridor, the proposal would restrict the type of retail on the ground level to “active” uses, relegating much of the space for banks and offices to the second floors. New buildings bigger than 60,000 square feet would have to reserve a portion of their space for entertainment or arts uses along much of the street, and the city is considering a density bonus for buildings that incorporate arts uses.

With rising land values of recent years causing a stir within the broader Harlem community — opposition has been stiff to Columbia University’s planned 17-acre expansion and housing advocates claim evictions from landlords shedding rent-regulated tenants are at an all time high — the city has had to walk a fine line while crafting the proposal. The area in which the proposed density is greatest tends to be mostly filled with low-rise retail stores, and the city added development restrictions to the sections of the corridor with considerable residential population. Still, the community has expressed concerns, proposing its own alternative that would decrease allowable building heights and expand provisions for arts and entertainment.

“I don’t want a 42nd Street — I don’t want a lot of tall high rises,” Council Member Inez Dickens said, calling for a height limit of about 19 stories.

The real estate industry, mostly content with the city’s proposal, is pushing for a greater density along the eastern end of the corridor, as the presence of the Metro-North stop, the nos. 4, 5, and 6 trains, and the proposed Second Avenue subway make the area very attractive for development.

“We thought that they could have given greater density as you got closer to the Metro-North station and the subways,” the president of the Real Estate Board of New York, Steven Spinola, said.

Both the City Planning Commission and the City Council must approve the plan.