A federal judge here held the clerk of the U.S. House of Representatives in contempt of court today for refusing to comply with a court order to turn over House documents sought by an insurance agent who is suing ABC-TV and several employes of a House committee.

In an unusual legal collision between the legislative and judicial branches of the government, U.S. District Court Senior Judge Edward S. Northrop imposed a $500-a-day fine on House clerk Benjamin J. Guthrie. The judge agreed to delay the fine for six days, giving Guthrie time to turn over the documents or appeal the contempt order.

The judge's action came after months of legal maneuvering by congressional attorneys and a resolution passed by the House April 28 ordering Guthrie not to produce the documents.

In a seven-page opinion, Northrop said it was "unfortunate" that the House had "deliberately ordered the clerk to disobey this court."

The judge added: "I cannot help but express my deep and profound concern that any member of Congress would vote in favor of a resolution which would bar evidence from a court of the United States. Such a blanket assumption of power questions the very integrity of our constitutional structure."

The fight over the documents stems from a $25 million civil lawsuit filed in 1979 by insurance agent George H. Benford of Glen Burnie, Md., who claims that ABC-TV, in conspiracy with investigators of the House Select Committee on Aging, surreptitiously taped him attempting to sell cancer insurance to two elderly women in Pikesville, Md. Portions of the tape were aired on the ABC Nightly News program.

The taping was part of an investigation begun in 1979 by the House committee into allegations that the insurance industry was pressuring elderly people to buy cancer insurance they did not need.

Benford, an independent agent for the American Family Life Assurance Co. of Columbus, Ga., sued ABC-TV and several House committee employes, claiming the taping violated Maryland antieavesdropping laws and ruined his career.

In preparation for the trial of Benford's suit, attorneys sought various House investigative documents relating to the Pikesville taping. House committee lawyers refused to furnish them, citing congressonal immunity and claiming that only House members can determine which of its investigative files should be made available to outsiders.

Benford then obtained an order from Judge Northrop directing the House committee to turn over the documents. When it refused, Northrop ordered the clerk held in contempt.

In its resolution last April, the House said Benford's court-backed subpeona for the documents was "an unwarranted and unconstitutional invasion of the House's constitutional prerogative to determine which of its proceedings shall be made public and in direct contravention of the constitutional protection for congressional investigative activity."

But Northrop said, "It is the province and duty of this court, and not the United States House of Representatives, to say what documents are and are not protected" from subpoena.

At another point, the judge said the House resolution ordering the clerk to disobey the court flies in the face of a fundamental ruling by U.S. Chief Justice John Marshall in 1803 that "it is emphatically the province and duty of the judicial department to say what the law is."