Donald Trump never seems to have trouble finding flaws.

Such was the case in November, some city officials tacitly acknowledge, when Mr. Trump obtained a building permit for a 45-story condominium hotel in a SoHo manufacturing district without any public review, exposing what many call a loophole in the city’s zoning regulations.

With Mr. Trump’s project likely to move forward, elected officials are now moving to examine possible changes in the zoning code so that future similar projects — condo hotels in areas zoned for manufacturing — cannot move forward without the standard level of public debate.

“Allowing development in manufacturing zones that is effectively residential in nature would have a dramatic negative impact on the neighborhoods we represent and on the city’s economy,” the president of Manhattan, Scott Stringer, wrote in a letter to the director of the city’s department of planning, Amanda Burden, on Monday.

The letter was also signed by the elected officials representing the area where the Trump SoHo project is now under construction, including Rep. Jerrold Nadler, state Senator Tom Duane, and Assemblywoman Deborah Glick. City Council Speaker Christine Quinn has also been pushing for action to prevent similar projects. Worried that the Trump SoHo project has set a precedent, they are asking the planning department to amend zoning regulations so that similar projects will not begin sprouting up across the city.

When the developers of the Trump SoHo announced their plans to build a 413-unit glass hotel condo in the middle of a lowrise neighborhood, they said condo buyers would only live in the building part of the year, which would qualifying it as a “transient hotel.” Hotels are considered asof-right in manufacturing zones, and the Trump project evaded the city’s more stringent uniform land use review process.

“There’s a reason why we have manufacturing districts, and we want to balance residential and manufacturing,” Mr. Stringer said in a telephone interview.

A spokeswoman for the Department of City Planning, Rachaele Raynoff, said regulating condo hotels in a manufacturing zone has never come up before, but the Planning Department has now begun to study the issue. “The desire to invest in the city has created a desire to make use of available land,” Ms. Raynoff said, and developers are expanding their options.

As changes to zoning regulations are explored, opponents say Mr. Trump’s claim that residents would be “transient” should be challenged in court. The executive director of the Greenwich Village Society for Historical Preservation, Andrew Berman, said the city is backing away from a legal challenge, perhaps because it was fearful of confronting Mr. Trump.

“Condo hotels, we believe, are not allowed by the zoning. If the city wants to allow them to go into this neighborhood, there is a process,” he said.

The city’s powerful real estate community has indicated it may not be amendable to a change in the current zoning regulations, which would seek to prevent condo hotels in manufacturing zones or seek to better define the term “transient.”

The president of the Real Estate Board of New York, Steven Spinola, said opponents seeking a zoning change care more about preventing tall buildings than closing a loophole on condo hotels.

“This happens to be New York City. I don’t understand why tall buildings are such a negative. No one wants them built, but everyone wants to live on the top floor,” Mr. Spinola said.

Even if the city soon pursues changes to the zoning regulations, the process could be lengthy, leaving open the option that other developers could follow Mr. Trump’s lead. Until the city stops it, Mr. Berman said, “Condo hotel development will explode because it’s so much more profitable and it’s so much easier to finance.”