A federal judge here has told leaders of Operation Rescue that the group will be fined $50,000 and the individual leaders as much as $5,000 if they ever again attempt, or help others, to block entrance to any clinics where abortions are performed in the District.

The fines would be some of the stiffest to be imposed on Operation Rescue, which has led blockades of medical clinics in many cities across the country in support of the group's antiabortion views, said Patricia Ireland, a vice president of the National Organization for Women, which brought the court action.

U.S. District Judge Louis F. Oberdorfer, ruling in the case last week, said he was basing the fines on the amount of money raised by the group in the District and the incomes of five Operation Rescue leaders.

Oberdorfer issued a preliminary injunction against Operation Rescue and its leaders on Nov. 8, after representatives of NOW, other women's rights groups and several medical clinics presented evidence that in the past, law enforcement officers had been unable to prevent blockades such as those planned for the District last Nov. 11 through Nov. 18.

Despite the injunction, members of Operation Rescue blockaded the Hillcrest Women's Surgi-Center on Pennsylvania Avenue SE on Nov. 11, and the Capital Women's Center and the Washington Surgi-Center, both on 22nd Street NW, six days later.

Oberdorfer also ruled last week that Operation Rescue and its leaders must pay damages of $1,680 to the Hillcrest Clinic, $533 to the Capitol Women's Center and $3,800 to the Washington Surgi-Clinic for expenses and physical damage incurred because of the blockades.

Oberdorfer issued a permanent injunction against Operation Rescue and its leader in January, prohibiting them, or "persons acting in concert with them," from "in any manner, or by any means, trespassing on, blockading, impeding or obstructing access to or egress from any facility at which abortions, family planning or gynecological services are performed in the District of Columbia."

Last week Oberdorfer amended the permanent injunction to cover anyone who "aids or abets" any of the proscribed acts.

The new fines will be levied if Operation Rescue or its leaders are found in contempt for violating the order. Money from the fines would be paid to the clinics that were blockaded, and individual fines would double with any successive blockade.