NEW YORK CITY—As hungry office developers move to the Far West Side and Downtown, they may soon come back to build in Manhattan's core business district: the Grand Central submarket. The New York City Department of Planning has unveiled plans to rezone parts of Madison and Lexington avenues to allow taller skyscrapers in Midtown East near Grand Central Terminal. Although questions remain about whether the city's aging infrastructure and transportation network can support it, experts tell Real Estate Forum the rezoning is necessary.

"In our most desirable Midtown core, we should be able to create new product," says Michael T. Cohen, president of Colliers Internationals Tri-State executive committee. "We're out of sites, we can't tear down what exists, we're stymied. Where do we build? We build at Hudson Yards, on Eighth Avenue, at the Trade Centers. But firms want to be on Sixth, Park and Madison."

Mitch Korbey, partner and head of Herrick, Feinstein LLP's land use practice, tells GlobeSt.com that given the size of some of the existing towers, demolition and rebuilding may not be viable. "However, a number of these buildings were built in the 1930s or 1940s, and in order to respond to the marketplace now and in the future, they're going to be modernized and rehabilitated," he says. "And given existing zoning, which might constrain them in terms of size, there's not a lot of incentive."