Since October, when President Carter was challenged in his campaign for the 1980 Democratic presidential nomination, the White House has beefed up its staff substantially through a time-honored technique -- borrowing employes from other government agencies.

Since Sen. Edward M. Kennedy (D-Mass.) announced his opposition to Carter, the number of White House "detailees" has increased from 25 to 70.

Like every recent president, Carter used detailee to augment the White House staff while not exceeding its personnel ceiling.

And in this season of political campaigning, many of these people are adding weight to the "liaison" and "constituency" chores of the presidency.

There is nothing illegal or new about this except that Carter promised repeatedly in 1976 that his administration would avoid the political games played by prior administrations with White House personnel.

Asked whether the almost threefold increase in White House detailees was related to the presidential campaign, Hugh Carter, the president's cousin who is in charge of White House personnel, said, "Not really."

He conceded, however, that some of the detailees may have done the regular work of White House staff members who went on vacation to campaign for the president. "Sure, some of the work overlaps," he said. "But the decision to increase the number of detailees was made last August," before Kennedy announced his candidacy.

Since September, at least 19 detailees have been loaned to the White House without ever working in the agencies that hired them. They were hired by a Cabinet department, at the request of the White House, and assigned to the White House staff the same day that they were put on the payroll.

The departments of Agriculture; Commerce; Energy; Health, Education and Welfare; Housing and Urban Development; Interior, Labor and Transportion have assisted the White House in this practice.

Many of these instant detailees ar working in White House offices that have quasi-political functions, even though detailees, unlike regular White House employes, are covered by the Hatch Act.Those assignments include the offices of Hamilton Jordan, White House chief of staff; Anne Wexler, a presidential assistant involved in building support for presidential programs, and Esteban Torres, in charge of Liaison with the Hispanic Community.

Torres has a staff of six, four of whom were placed in jobs, at his request, in the labor Department before they were detailed to the White House on the day they were hired. "The Labor Department is one of the most cooperative of the agencies," Torres said. A fifth member of his staff is on loan from the Office of Personnel Managment.

Asked to justify this situation, Torres said, "One of the principal reasons is that the White House has a limitation on the number of staff." The White House personnel ceiling is still significantly lower than in other recent administrations, consistent with Carter's well-publicized campaign promise to reduce staff size.

A government official explained how the game is played with detailees: "Everyone in the White House -- Esteban Torres, Anne Wexler and so on -- were going to their friends in the agencies and saying, 'You've got to help me out.' Eventually the whole thing got out of hand and was so obviously inconsistent with administration policy that the whole thing was centralized in Hugh Carter's office."

Hugh Carter denied that "there was ever a loss control" over the detailing process.

This practice of detailing workers to the White House, especially for campaign seasons, goes back at least as far as the administration of Lyndon B. Johnson in the 1960s. There is argument over whether President Carter's practice of same-day "detailees" -- hired and transferred simultaneously -- is unique.

Rep. Dick B. Cheney, (R-Wyo.) said that, to the best of his knowledge, the Ford Administration, in which he was White House chief of staff, never hired someone for an agency and then detailed him to the White House the same day.

Based on an examination by his office of old personnel records, Hugh Carter said that on March 1, 1976, 21 percent of those detailed to the Ford White House were "new placements," and that examples of this practice go back to the Kennedy administration.

He acknowledged that 16 of the 57 people detailed to the White House since last Oct. 1 were "new placements." At the same time, some former detailees have left.) He said that this proportion of instant detailees -- 28 percent -- has remained relatively constant since President Carter took office.

In any case, the records show that since the campaign started last fall, the number of White House detailees has nearly tripled.

Hugh Carter attributed this increase to such factors as improved White House management, new efforts to build a consensus for the president's programs, increased contacts with constituency groups and the crises in Afghanistan and Iran. He did not mention President Carter's reelection campaign.

According to the Office of Personnel Management, there is nothing illegal or improper in assigning a detailee to the White House as soon as that person is put on an agency payroll. "The White House would not request a detailee unless there was some urgent need," said Robert Woordrum, the agency's director of public affairs.

Hugh Carter took a similar tack: "If we go to an agency and ask for somebody to help us and they don't have anyone they can spare or don't have anybody with that expertise, the agencies have been amenable to helping us by our recruiting people for them. There is nothing wrong with that or inappropriate or illegal."

Hugh Carter stressed that all the instant detailees were either Schedule C political appointees, or in similar political positions, or were temporary employes of the agencies. None was placed on the regular Civil Service rolls, he said, adding, "We have taken great pains to make sure everything is straight."

One example of how the instant detail process works is the case of Kelly Muchoney, who until Oct. 6 was on the staff of the White House news summary.

On Oct. 7, Muchoney went on the payroll of the Department of Energy as a GS-8 energy program assistant. The same day she was detailed to the White House speakers bureau, where she goes over speaking requests and helps arrange appearances by surrogate speakers for the president.

There were two reasons for the transfer, Muchoney said: "One was because of the White House personnel count and the other was for agencies to be represented on the speakers bureau." Muchoney works exclusively on energy speeches.

Another White House detailee is Bernard Aronson, chief White House Speechwriter for much of 1979. He recently became a deputy to Landon Butler, Hamilton Jordan's assistant who handles labor affairs. But Aronson is currently carried on the Labor Department payroll as a Gs-15 special assistant to the secretary of labor.

The entire question of detailing is one that makes the Carter White House uneasy. A number of White House staff members, who are on detail, received explicit instructions to refer all questions about their assignments to the White House press office.

Both Hugh Carter and Torres took great pains to argue that the details in the office of Hispanic liaison could just as easily be doing the same work at the Department of Labor, which has four of the detailees on its payroll. However, one of the detailees from the Labor Department, Suzane Gomez-Collins, serves as Torres' personal secretary, a job that would be difficult to carry out from the Labor Department's offices at 200 Constitution Ave.

When pressed for the dates of her employment at the Labor Department, she said, "I don't remember," then she placed her phone on "hold" and conferred with someone in her office. When she came back on the line, she conceded that she had come to the White House directly from her last post with Eastern Airlines.

Gomez-Collins, who is listed on the Labor Department rolls as a GS-11 confidential staff assistant, initially claimed that she had last worked as a special assistant to Labor Secretary Ray Marshall.