A coalition of advocacy groups for federal food programs has joined the fray against the President's Private Sector Survey on Cost Control, filing suit to stop the controversial advisory group from making any recommendations about the operation of domestic food programs.

In a motion for a preliminary injunction filed in U.S. District Court here, the National Anti-Hunger Coalition said the cost-control survey, three of its task forces and the Commerce Department are "in flagrant violation" of requirements of the Federal Advisory Committee Act and "are attempting to avoid any public scrutiny of, or involvement in, the affairs of a powerful advisory body which is evaluating practically every federal program and function."

The survey is a group of private businessmen brought together by President Reagan last June to advise him on ways to improve government management and reduce costs. The activities of the survey and its 35 task forces already have come under fire from Capitol Hill, and a congressional committee has subpoenaed various documents regarding its work.

The Justice Department, which has been staving off that subpoena with one hand, now has the other hand busy with the lawsuit. Department lawyers last week asked the court to delay a hearing on the motion until Jan. 20, and promised that the survey and its task forces will not meet or send over any recommendations on food programs until Jan. 31.

In the meantime, Reagan has signed an executive order extending the cost-control survey for another six months, through June 30, 1983. It had been scheduled to go out of business at the end of 1982