The Bloomberg administration is warning that a City Council bill that would stop trusting homebuilders to certify that their construction projects obey zoning and building codes could hinder economic development in New York City.

The Department of Buildings relies on many builders to “self-certify” their projects, under a Giuliani-era program to speed development. But a bill to be introduced Thursday by Council Member David Weprin, a Democrat of Queens, would end self-certification for homes and require that the city examine all major construction plans for one-, two-, and three-family homes.

Currently, the city aims to audit 20% of the self-certified building applications it receives every year, a spokeswoman for the buildings department, Kate Lindquist, said.

Mr. Weprin’s staff concedes that the bill does not provide funding for the staffing the proposal would inevitably require. But the bill’s supporters, noting that allegations about shoddy construction are the most common complaint lawmakers receive from constituents, say minor delays are a necessary tradeoff to protect the safety and character of neighborhoods.

Community groups blame the self-certification process for construction woes, including several high-profile building collapses and homeowners being scammed by sloppy remodeling jobs.

“The Department of Buildings has completely lost control of the honor system that allows builders and architects to sign off on their own work,” Mr. Weprin said at a news conference at City Hall yesterday. “As a result, we have developers acting with complete impunity with the only people that are truly watching being the community members.”

Mr. Weprin and several of his colleagues were surrounded by dozens of New Yorkers, who spoke of unscrupulous and dangerous construction sites in their neighborhoods.

The Bloomberg administration is backing another measure, from Council Member James Vacca of the Bronx, that officials say would implement a strike system to bar builders who repeatedly flout the rules from self-certifying. Mr. Vacca’s bill, which Mr. Weprin supports, would apply to all construction in the city.

“Abolishing the program would require significantly more resources than we have available to us today,” Ms. Lindquist said in a statement. “What’s more, it could hinder good, healthy economic development that this city needs.”

The president of the Brooklyn chapter of the American Institute of Architects, Dmitriy Shenker, said he welcomed more review but questioned whether the city had enough qualified staff to review plans on a timely basis.

The city receives about 70,000 building applications a year.