An American Bar Association task force on crime has recommended the use of "preventive detention" to keep potentially dangerous criminal suspects off the streets while awaiting trial.

The task force thus joins Reagan administration and congressional conservatives in what appears to be an increasingly powerful campaign for preventive detention leeislation, opposed by civil liberties groups as an excessive infringement on rights of defendants.

The task force, headed by former Florida prosecutor Richard E. Gerstein, is composed of nine lawyers, judges and scholars. Its proposals eventually will be submitted for full ABA approval.

The task force called for stricter gun-control laws as well, but rejected measures to ban handgun possession for individuals in their homes and businesses, as many gun-control groups favor.

And it took sharp issue with administration proposals for a massive infusion of funds to build more and bigger prisons. "There is no solid evidence to support the conclusion that sending more convicted offenders to prison for longer periods of time will deter others from committing crimes," the ABA task force said. Nor is there reason to believe greater rates of incarceration would reduce the crime rates, because so few criminals get caught, it said.

The issue of preventive detention -now before the Supreme Court -has been hotly debated for several decades, but except in the District of Columbia and a few states, laws mandating its use have been rejected on civil liberties grounds. Under preventive detention, people charged with crimes can be locked up before trial without a right to bail when it is thought they might be dangerous.

The task force said preventive detention should only be used under careful procedural safeguards and special hearings in which the suspect's dangerousness is considered. Defendants should only be preventively detained, it said, when they are accused of committing a violent crime while on release for a previous offense and when they have a past record of violent crime.

The task force did disagree with conservatives on the "exclusionary rule," which forbids the use of evidence illegally seized by police. The exclusionary rule has also been under attack for years as allowing otherwise guilty criminals to go free "on a technicality." The administration has proposed creating an exception to the rule when police act unconstitutionally but in "good faith."

The task force criticized that proposal. "Public policy militatees against a lesser standard for admission of evidence in criminal proceedings, such as is proposed with 'good faith' exception. Existence of the rule has contributed greatly to law enforcement professionalism at the local, state and federal levels."