Federal prosecutors increasingly are asking D.C. Superior Court judges to use "preventive detention" as a means of getting suspects accused of serious crimes off the streets while they await trial.

Preventive detention is a rarely invoked tool by which prosecutors can ask judges to hold suspects with prior records who are accused of various serious crimes without bond before trial because they are considered too dangerous to be released. In the last five years, preventive detention has been granted by judges about 55 of the 65 times prosecutors have requested it.

"As one response to the increasing crime rate and the community concern, it is the policy of this office, our resources permitting, to seek preventive detention in an increased number of cases, where the facts and law justify it," said U.S. Attorney Charles F. C. Ruff.

He added that the longstanding criticism that preventive detention violates a suspect's right to be presumed innocent before trial "has lost some of its knee-jerk quality."

In the District, the preventive detention law has been interpreted to mean that the U.S. Attorney's office must make a request of a judge to detain a criminal suspect. The vast majority of D.C. criminal suspects are released on bond. If a suspect is not dangerous enough to hold without bond, a judge can set other conditions to protect the community, such as ordering that the suspect stay away from complaining witnesses.

In addition, a judge must consider whether a defendant will appear for his next court date and can set a money bond for that reason. In recent months, such highly publicized defendents as Bernard C. Welch, accused slayer of Washington cardiologist Michael Halberstam, and Daivd I. Garris, convicted for the slaying of a WMAL radio advertising executive, were preventively detained. Preventive detention also has been used in cases involving rape, robbery and burglary suspects with extensive criminal records.

Prosecutors occasionally have been criticized for not using preventive detention in cases in which suspects committed another offense while awaiting trial.

Statistics indicate that Ruff's plans may receive support: In 1979, prosecutors were granted only three requests to detain suspects; in 1980, prosecutors made 12 such requests and 10 were granted. Four requests already have been made in the first six weeks of 1981; two were denied and two are pending.

"You have to look at it as one piece of a much larger puzzle," Ruff said. "We try to deal with the most serious offenders with our most serious sanctions."

The D.C. preventive detention law was passed a decade ago and was highly controversial. Civil rights advocates strongly opposed it at the time and still do. The American Civil Liberties Union "opposes all forms of preventive detention," a spokesman said yesterday. "[It] is an extremely dangerous procedure . . . We don't think the court system has the ability to predict who is going to commit a crime in the future and who is not."

The decision to increase the use of preventive detention comes at a time when U.S. Chief Justice Warren E. Burger has called for giving judges greater leeway to lock up potentially dangerous defendants. Locally, there have been calls for greater police and prosecutor enforcement.

Some defense attorneys claimed yesterday that the U.S. Attorney's office only uses preventive detention in highly publicized cases as an exercise in public relations. "It seems that every time a case is in the public eye, they [ask for preventive detention] to show they are being tough on crime," said attorney Christopher G. Hoge, who defeneded Garris.

"The notion that we somehow use preventive detention for public relations purposes is nonsense," Ruff retorted. The fact that preventive detention is requested in cases of serious offenders involved in highly publicized crimes is "mere coincidence," Ruff said. "It does not mean there is a cause-and-effect relationship. That's absolute nonsense."

Another attorney who defended a suspect who was detained said: "The whole history of our criminal procedures is to protect liberty and make sure that as times get harder, as crime goes up, or when there's an especially large outcry, we don't start making decisions on an expedient basis."

Attorneys for the District's Public Defender Service have challenged the constitutionality of preventive detention before the D.C. Court of Appeals. cThey contend that the law violates accused suspects' constitutional rights by effectively sentencing them to jail before they have been found guilty of a crime.

Bruce D. Beaudin, director of the District's Pretrial Services Agency, which makes recommendations to judges as to whether a defendant should be released or preventively detained, welcomed Ruff's action.

"I think it's long overdue -- for both the community's benefits and that of the defendant," he said. "[Preventive detention] means we won't be putting people in jail just because they can't make money bail, or releasing people who should not be released just because they can make bond. But if somebody goes through a preventive detention hearing, it means the government has a case, and there has been a finding that there's some dangerousness."

In every case in which defendants have been preventively detained since 1976, prosecutors have won convictions or guilty pleas, although in some cases to lesser charges than the suspects originally faced.