“I don’t like the idea of the government snooping,” said Dr. Raymond Scalettar, an internist in Washington. “It’s a pernicious practice — Big Brother tactics, which should be opposed.”

According to government documents obtained from Obama administration officials, the mystery shoppers will call medical practices and ask if doctors are accepting new patients and, if so, how long the wait would be. The government is eager to know whether doctors give different answers to callers depending on whether they have public insurance, like Medicaid, or private insurance, like Blue Cross and Blue Shield.

Dr. George J. Petruncio, a family doctor in Turnersville, N.J., said: “This is not a way to build trust in government. Why should I trust someone who does not correctly identify himself?”

Dr. Stephen C. Albrecht, a family doctor in Olympia, Wash., said: “If federal officials are worried about access to care, they could help us. They don’t have to spy on us.”