Rep. John M. Murphy (D-N.Y.) has asked the Justice Department to investigate the sources of recent newspaper articles critical of him.

Murphy, the subject of investigations by the Justice Department, the Securities and Exchange Commission and the Internal Revenue Service, wrote to Attorney General Benjamin R. Civiletti demanding an immediate probe of possible leaks to reporters.

The only article Murphy identified in his Oct. 2 letter was a Sept. 24 story by Jack Newfield in the Village Voice headlined "The Worst Congressman."

The senior congressman from New York charged that "unsubstantiated testimony and documents" had been leaked to Newfield and other journalists, possibly by Justice Department officials.

Murphy refused to discuss his letter and referred inquiries to the Justice Department. Robert Havel, a spokesman for justice, summarized the letter and said Richard Rogers, acting director of the Office of Professional Responsibility, had met with Murphy to discuss his charges.

"I want to stress that there's no investigation of any reporters or any newspapers," Havel said. "If someone makes a complaint against . . .Justice Department employes it's incumbent on us to look into it."

Newfield, who has been looking into Murphy's affairs for almost a year, said he fears that a Justice Department investigation could intimidate sources.

John Shattuck, legislative director of the Washington office of the American Civil Liberties Union, said, "This kind of use of congressional power to deal with critics in the pres is a disturbing inroad on the First Admendment and is likely to chill investigative reporting."

Justice Department officials disagreed. If the investigation Murphy has asked for is authorized and follows the established pattern, one source said, all of those assigned to the case would be asked to sign affidavits that they haven't leaked information to Newfield or any other reporter. "That's been the end of it before," he said.

No reporter has even been questioned in the handful of similar investigations that Justice has conducted, a source said.

In his letter to Civiletti, Murphy said also that an investigation of leaks had been requested of the U.S. attorney's office for the Southern District of New York. Assistant U.S. Attorney Patricia Hines and Murphy's lawyer, Andrew Maloney, refused to comment. The Manhattan U.S. attorney's office is conducting one of the investigations of the congressman.

Murphy apparently has reacted to at least one earlier critical article by calling for an investigation.

In a long reply to Newfield, published as a two-page advertisement in the Village Voice after the weekly paper refused to consider printing free any reply over 800 words long, Murphy said an FBI investigation found errors in a Washington Star story about him.

He said in the $4,500 ad that the FBI probe proved that charges that Murphy had represented the interests of Thomas Gambino, a son of the late Mafia leader Carlos Gambino, were inaccurate.

Jerry Oppenheimer, who wrote the Star article, said that he knew of no such proof and that he was unaware of any Fbi investigation of leaks as a result of his story.