The largest money market fund in the Washington area has been bilked of $1.55 million by one of its clerks who allegedly transferred the money into the bank account of a friend who then deposited it in a Swiss bank account, according to papers filed by the fund in federal court.

The funds, First Variable Rate Fund for Government Income Inc., said it was insured for the loss and its shareholders will not be affected by the alleged swindle. The fund has assets of $788 million.

Fund officials said they have been unable to recover the money or locate the two individuals allegedly involved in the scheme.

In a petition for attachment filed late last week in U.S. District Court in Alexandria, the fund charged that Vera Lucia Campos, an employe whose duties permitted her to monitor transactions and prepare customer statements, transferred the money on about May 5 to the account of Andre L. Prestes at Virginia National Bank. The court papers charged that Campos transferred the money "with intent to steal, convert and embezzle."

The fund said that Campos, who had been employed five months, and Prestes are of Brazilian origin and enjoy "a close personal relationship." Campos listed an address in Alexandria and Prestes last lived in Arlington. c

The transaction apparently could take place because Presters, who had invested $2,500 in the fund, had asked that repayment of his interest in the fund be made through his account at Virginia National.

Several days later, on about May 7, Prestes withdrew $50,000 from the Virginia National account, according to the court papers. The next day Campos quit her job with First Variable. Fund officials charged the Prestes then transferred some, if not all" of the remaining $1.5 million to Swiss Bank Corporation. About two days later, they said, the money was transferred to Union Bank of Switzerland.

A First Variable official said that a man identifying himself as Prestes called the fund after the money went to a Swiss account to complain that $97 had been withdrawn from the $1.5 million to cover the costs of the computer transfer. The transfer should have only cost $35.

It wasn't until the beginning of June, however, that First Variable officials discovered what had happened. Last week the fund asked the court to order the two to return the money and to attach their property, including the bank accounts.In addition, the fund has asked the judge to freeze the accounts and order the banks to disclose information about the accounts and the transfers.

"The appropriate authorities have been notified and all necessary steps are being taken to recover the money and locate the persons believed to be involved," said Wayne Bardsley, secretary and general counsel of First Variable.

Bardsley said the fund is protected against the loss by a fidelity insurance company. "Moreover, the fund's adviser has agreed to assume any costs or expenses which may not be covered by the fund's insurance policies,' Bardsley added. The adviser is Government Securities Management Co., a company that assists First Variable in running the growing money market venture.

The fund, which went into business in December 1976, says in its advertisements that it invests solely in U.S. government-backed notes and other obligations.