Mayor Bloomberg and City Council Speaker Christine Quinn unveiled a package of more than a dozen legislative proposals yesterday that they said would help improve safety at construction sites.

“Our priority is not to balance two competing forces — economic development and safety,” Mr. Bloomberg said yesterday at a press conference with representatives from the construction industry and labor unions at City Hall. “It is — it has to be — safety.”

Under the legislation, general contractors and subcontractors who work in concrete and demolition operations would have to register with the Department of Buildings as part of a new system that would track their safety performance over time. Contractors with repeat violations could see their construction work shut down across the board rather than at individual sites. The buildings department would also gain the authority to assign a project safety monitor to construction sites that fail to meet safety standards and bill the contractor for the costs of the monitor’s work.

The city’s acting buildings commissioner, Robert LiMandri, said that these changes, which would give the city greater leverage to enforce safety regulations as a corrective action against repeat offenders, could be meted out more broadly than in the past.

“We will suspend or revoke their ability to do business in this city,” Mr. LiMandri said. “That’s not something we can do now.”

The announcement comes in the wake of a fatal crane collapse at East 91st Street that left two construction workers dead and temporarily forced residents from their homes. The accident was the most recent in a string of fatal construction accidents this year and followed another crane collapse in March at East 51st Street that killed seven people and destroyed a townhouse. The city’s buildings commissioner at the time, Patricia Lancaster, resigned in April, leaving Mr. LiMandri to run the department until a permanent replacement could be found.

Under the legislation, workers who perform rigging operations on tower cranes would have to undergo 30 hours of training beforehand and take an eight-hour refresher course every three years afterward. Investigators believe a broken nylon sling caused the March collapse and the legislation would require both that such slings be used only when their manufacturer’s manual specifically approves and that measures are taken to soften any sharp edges that could damage the sling.

The president of Manhattan, Scott Stringer, who has often criticized city government’s record on construction safety, said that while he agreed with Mr. Bloomberg’s proposed reforms, he believed that their implementation required an overhaul of the buildings department to succeed.

“No one is asking the fundamental question: ‘Can they do it?'” Mr. Stringer said yesterday at a press conference. “Nobody is asking, ‘Do we have the trained personnel today that is necessary to do this job?'”

He recommended that the city complete a top-to-bottom review of the buildings department’s capacity to comply with the proposed legislation and suggested that other agencies, such as the police and fire departments, should be brought in to assist.