Mayor Michael Bloomberg said the bill to increase scrutiny of the city's outside contracting was "not a good bill for the city" hours after it had passed overwhelmingly in the City Council Thursday.

The bill — known as the "Outsourcing Accountability Act" — had called for the city to perform a cost-benefit analysis to document the outsourcing actually saves the city money. Supporters said it would help prevent another CityTime contracting scandal.

CityTime, an outsourced re-design of the city's payroll system, was supposed to cost $70 million, but it wound up costing 10 times that. According to prosecutors, CityTime became a multi-tiered fraud that resulted in the indictments of several contractors and the loss of hundreds of millions of City dollars.

City Council Speaker Christine Quinn said the new law would bring additional transparency to outsourcing that costs the city as much as $10 billion this year alone. The proposed legislation would have required city agencies to look ahead one year and publicly disclose plans for soliciting outside contractors and vendors.

"We are talking about billions of dollars at a time when we are having to cut back in other areas. So the question has to be how do you deliver services most efficiently," Quinn said during a recent interview.

Earlier, a spokesperson for Bloomberg said the mayor opposed the legislation because it would add unnecessary red tape that would slow down city agencies' efforts to improve services and solve problems.

Carol Kellerman, executive director with the non-partisan Citizens Budget Committee, said Quinn's bill has a lot going for it, but needs fine-tuning.

"This bill expands the use of cost-benefit analysis, which is an important tool for ensuring government efficiency," Kellerman said. "It also requires the development of a comprehensive contracting plan, which  is a welcome step in transparency and coordination. ... But the three-year look-back period for analyzing contracts is too long and will be burdensome to implement."

The growth of city outsourcing is a hot-button issue for the city's municipal unions, which historically have been kingmakers in citywide elections.

The unions say the increased reliance on contractors has led to the waste of hundreds of millions of dollars in taxpayer dollars even as the Bloomberg Administration has pushed for labor concessions and threatened layoffs.