Leaders of the Free South Africa Movement expanded their antiapartheid campaign to the downtown office of Deak-Perera yesterday, forcing the foreign exchange and precious metals firm to close for the afternoon after a sit-in protesting the sale of Krugerrands was staged at its entrance.

The Washington office manager, after consulting with the firm's New York headquarters, declined to file a complaint against the protesters, and police did not arrest them.

"They won't sell Krugerrands if they don't open their doors," said Randall Robinson, coordinator of apartheid protests that have been a weekday ritual at the South African Embassy here since Nov. 21. He spent about 45 minutes inside Deak-Perera yesterday, holding up a "Ban the Kruggerrand" sign in its window while about 15 Free South Africa Movement supporters chanted and picketed outside.

Robinson, D.C. Del. Walter Fauntroy and three other veterans of the embassy protests later blocked the entrance to the firm's 18th and K streets NW office. They issued a statement calling Krugerrand purchases in the United States "a direct investment in the South African way of life" and a profitable transaction for the South African government since gold for the coins "is extracted from the earth by the semislave labor of blacks."

The sit-in was aimed at Deak-Perera, a target of earlier apartheid protests in Boston, because the company is the major dealer in Krugerrands. But the demonstration also was an attempt to force the rearrest -- and public trial -- of protesters whom the U.S. attorney's office here so far has refused to prosecute.

U.S. Attorney Joseph diGenova has dropped misdemeanor charges against several hundred embassy protesters, arguing that the court system should not be clogged with such civil disobedience cases. He has warned, however, that he will prosecute repeat offenders.

The five who joined in yesterday's Deak-Perera sit-in -- Robinson, Fauntroy, Mary Frances Berry, Sylvia Hill and Roger Wilkins -- are all members of the Free South Africa Movement steering committee. Robinson, Fauntroy and Berry spent Thanksgiving Eve in jail after they held a sit-in in South African Ambassador Bernardus Fourie's office.

Rearrests at Deak-Perera might have resulted in the jury trials apartheid protest organizers have been seeking to focus public attention on the policies of South Africa and U.S. relations with it. Protesters are seeking an end of U.S. policy that aims to bring about reform in South Africe through constructive engagement with its government.

In Boston, 13 protesters, including Nobel laureate Dr. George Wald and two members of the Boston City Council, face jury trials this month on charges of trespassing at Deak-Perera offices there. Other trials are set for protesters who have demonstrated at the home of South Africa's consul in Seattle.

Deak-Perera would not comment on the protest, and their customers yesterday seemed clearly annoyed to find the door locked and their paths blocked by demonstrators.

Robinson said the protesters will be back if the firm continues to sell Krugerrands. He also warned other South African coin dealers, including nearby W. Bell & Co. Inc. that "they should be concerned as well."

Krugerrand sales constitute one-fourth of the value of all South African exports to the U.S. and last year amounted to more than $484 million, protesters said.