Federal and state officials, many facing record budget deficits, are starting to aggressively pursue companies that try to pass off regular employees as independent contractors.

President Obama’s 2010 budget assumes that the federal crackdown will yield at least $7 billion over 10 years. More than two dozen states also have stepped up enforcement, often by enacting stricter penalties for misclassifying workers.

Many workplace experts say a growing number of companies have maneuvered to cut costs by wrongly classifying regular employees as independent contractors, though they often are given desks, phone lines and assignments just like regular employees. Moreover, the experts say, workers have become more reluctant to challenge such practices, given the tough job market.

Companies that pass off employees as independent contractors avoid paying Social Security, Medicare and unemployment insurance taxes for those workers. Companies do not withhold income taxes from contractors’ paychecks, and several studies have indicated that, on average, misclassified independent workers do not report 30 percent of their income.