A federal judge has refused to grant immunity to Dr. Murdock Head, the director of a large Virginia foundation who has been implicated in a congressional influence-peddling scheme, following Justice Department disclosures that Head has become "the target" of a grand jury investigation in Alexandria.

The request for a grant of immunity from prosecution came not from Head or his lawyers, but from lawyers for Rep. Daniel J. Flood (D-Pa.), who goes on trial in Washington Monday on charges of accepting cash from Head and others in return for his help in winning federal projects.

District Judge Oliver Gasch's refusal to grant Head the immunity last week was the first confirmation that a grand jury investigation of Head, which began last spring in Washington, had moved to Northern Virginia.

Justice Department lawyers had argued against the immunity request, saying in court papers that their investigation had produced "a number of government witnesses" who would back their earlier statements that Head funneled $27,000 to Flood through the congressman's former top aide, Stephen B. Elko.

Prosecutors have alleged that Head, a George Washington University department head and director of the nonprofit Airlie Foundation in Warrenton, gave the money to win assurance of federal contracts for his department and the foundation.

Flood's lawyers claimed they needed Head's testimony for their defense, but said Head would not testify unless he could be assured immunity from prosecution. Government lawyers agreed that Head would invoke his Fifth Amendment guarantees against self-incrimination if called for the Flood case, but said an immunity grant would ruin their investigation of Head.

Gasch, in a Jan. 4 ruling sided with the prosecutors. "In view of the fact that the government has represented that Dr. Head is presently the subject of an extensive grand jury inquiry in the eastern [court] district of Virginia, the court concludes that it would be improper" to grant Head immunity "at this time," Gasch said.

Head, who has degrees in medicine, law and dentistry, has repeatedly asserted he is innocent of any wrong-doing.

Ray Randolph, a Washington lawyer representing Head, confirmed yesterday that he would advise Head not to testify at the Flood trial without a grant of immunity. Randolph said such advice would be routine for any client under investigation.

Flood, a 74-year-old colorful 15-term congressman from the Wilkes-Barre, Pa., area, has pleaded innocent to the charges that he traded his influence as chairman of a key House Appropriations subcommittee in exchange for cash and bank stock, from Head and others.

Head first was accused last year by Elko of funneling $87,000 to Flood, former Rep. Otto Passman of Louisiana and Elko himself, according to an affidavit filed in a Los Angeles court. Elko was convicted in 1977 of accepting bribes from a California trade school seeking federal funds.

William E. Cummings, U.S. attorney in Alexandria, declined yesterday to discuss the grand jury investigation into Head's activities. The Airlie Foundation, which sits on more than 1,000 acres of pristine farmland outside Warrenton, has done millions of dollars in business with the federal government.

Head, who is on a one-year sabbatical from his post as head of the George Washington University Medical Center department of medical and public affairs, came under increasing scrutiny last year when his name came up in the Flood case.

In April, the Agency for International Development terminated a $1 million-a-year population study project between the agency and a George Washington University group run by Head, but denied that other termination was connected to publicity tying Head to Flood.