Spitzer, speaking to the Long Island Federation of Labor's constitution convention, said the moratorium is necessary because too many contractor-run apprenticeship programs have low graduation rates. He suggested contractors prefer it that way so they don't have to pay higher wages.

Spitzer, a Democrat, said the Department of Labor will review its certification process for the programs and examine existing training efforts to ensure they're fair to workers.

But critics on Tuesday said the governor's surprise move was unfair to non-union contractors, especially as a growing number of cities and towns require that contractors have training programs in place to bid on government construction contracts.

Trade unions typically have long-standing training programs that supply workers to union builders. Non-union builders, on the other hand, are less likely to have such programs, but have been adding them in recent years in response to the laws.

"This will put a halt to the growing number of contractors who have been applying to have training programs," said Scott Zylka, a spokesman for the New York state branch of Associated Builders and Contractors Inc., a trade group with many non-union members. "The unions think public works is their domain, and they think non-union contractors should stay out of it."

Adding to concern, Zylka said, is a proposed change to the law that guides the process for public construction projects. The change to the so-called Wicks Law would require that bidders on the contracts have training programs in place, he said.

"You can see how they're setting this up," Zylka said. "Unfortunately, it's now time for the governor to set up his union supporters for their help during the campaign."

Mark Hansen, a spokesman for Senate Majority Leader Joseph L. Bruno said state leaders had agreed earlier this year on revisions to the Wicks Law, but said the state Senate had not voted on the revisions.

Hansen said Bruno will review and consider Spitzer's moratorium and its potential impacts.

Leo Rosales, spokesman for the state Department of Labor, said the moratorium is only about ensuring that training programs benefit those they are supposed to help.

"We're looking out for the workers, which is what the Department of Labor is supposed to do," he said.

Union leaders cheered the moratorium, saying on Tuesday that the growth of non-union training programs has long been one of their concerns. They suggested union training programs offer far superior levels of instruction than their non-union counterparts.

Mario Cilento, chief of staff for the New York state AFL-CIO, said the governor had taken a stand for workers, and though he conceded the moratorium would aid union training programs, he downplayed the chance that changes to the Wicks Law would give the moratorium added punch.

"It would be premature to start assuming that," Cilento said. "We don't even know that there's going to be changes."