House subcommittee investigators yesterday said they have reached an agreement with the White House that provides them with "direct access" to President Reagan's 1980 campaign files.

The compromise arrangement will rely largely on the General Accounting Office, a nonpartisan auditing agency that is under Congress' control, to screen the campaign documents and determine which are relevant to the panel's inquiry.

GAO auditors will be allowed to inspect the individual campaign files of a dozen Reagan campaign aides, including CIA Director William J. Casey, White House chief of staff James A. Baker III, White House communications director David R. Gergen and former national security affairs adviser Richard V. Allen.

The six-page agreement, which avoids a potentially divisive battle over House subpoenas, was hammered out during weeks of negotiations between White House counsel Fred F. Fielding and James Hamilton, special counsel to the House Post Office and Civil Service subcommittee on human resources.

"Direct access to these files is very important to our ability to complete our work," said subcommittee Chairman Donald J. Albosta (D-Mich.), who is heading the inquiry into how Reagan's 1980 campaign obtained documents and information from the Carter White House.

The GAO inspection of the Reagan files, stored at the Hoover Institution at Stanford University, is to begin next week.

FBI agents and the Hoover archivist may be present at the GAO review and can raise objections about the relevancy of documents before they are copied for the subcommittee. The agreement does not spell out who has the final authority in the event of a dispute, but Albosta said he doesn't expect any problems and is confident that the FBI would not engage in a "cover-up."

"The fact would still remain that we would know what was there that was relevant to our investigation," Albosta said, adding that the subcommittee could decide later whether to subpoena the material.

In addition to the GAO review, the FBI and the Hoover archivist are to give the subcommittee all campaign documents involving the 1980 debate between Reagan and President Carter, the unauthorized transfer of campaign material, national security information or "documents which may show any intelligence operation organized by the Reagan-Bush campaign . . . ."

The administration, which already has agreed to turn over most of the records the Justice Department has acquired in the case, said it was pleased with the compromise.

"The president wants all the facts of this controversy to become known as soon as possible and is hopeful that this agreement will contribute to that goal," White House spokesman Anson Franklin said.

Subcommittee staff director Micah Green, who had rejected previous proposals to have the Hoover Institution files screened by the FBI, said: "We will not be depending on the product of others . . . . The files we'll have access to will include things the FBI hasn't pulled."

Administration officials have expressed concern about the release of peripheral, but politically embarrassing, material, but Green said the panel agreed not to copy or take notes on campaign documents that are not relevant to the probe. He added, however, that evidence of "dirty tricks" by the Reagan campaign would be deemed relevant.

The subcommittee's request for individual files provided a rough guide of the panel's interest in selected Reagan campaign aides. These include former campaign manager Casey; Baker, who coordinated plans for the debate; Allen, who has said he received material from Carter's National Security Council; Robert K. Gray, now head of a Washington public relations firm, who handled communications for the campaign; Francis S.M. Hodsoll, who assisted Baker on the debate and is now chairman of the National Endowment for the Arts, and Anthony Dolan, who did negative research on Carter, was close to Casey and is now a top presidential speech writer.

Several on the list have intelligence connections, such as Robert Garrick, a retired admiral who had former military officers monitor air bases for an anticipated "October surprise" by Carter; Stef Halper, who used a network of "think tank" people for negative campaign research; Robert Gambino, a former CIA security officer who monitored the news media for Halper; and Max Hugel, formerly the CIA's director of clandestine operations, who worked with constituency groups.

The FBI yesterday allowed subcommittee officials to view videotapes of Reagan's practice sessions for his Oct. 28, 1980, debate with Carter. They declined to say whether the tapes show participants discussing the receipt of Carter's debate briefing book.

On another matter, on Thursday Albosta told House Minority Leader Robert H. Michel (R-Ill.) that he will not ignore allegations that Carter administration officials did campaign work on government time.

"This a thicket which troubles every administration," Albosta wrote Michel. "Unfortunately, the law on what is or is not permitted is not as clear as your letter suggests."

Albosta said that his staff would raise the issue with Reagan and Carter aides but that it may go beyond the panel's jurisdiction.