Sen. Paul Simon (D-Ill.) threatened yesterday to try to block the nomination of Laurence H. Silberman to the U.S. Court of Appeals here unless Silberman resigns from an all-male club.

Silberman, a former deputy attorney general and one-time ambassador to Yugoslavia, said yesterday at his Senate confirmation hearing that he belongs to the Metropolitan Club at 17th and H streets NW, which has no women members.

"I believe it would be wise for the club to admit women," Silberman said, but he said in response to a question from Simon that he believe no women have ever been "put up" for membership. But Silberman said he would "rather not" resign from the 122-year-old club unless the rules of judicial behavior oblige him to do so.

Simon then asked Silberman to reflect on his membership and said later in an interview that he would put a hold on the nomination unless Silberman quit.

Last night, Metropolitan Club President John A. Sargent declined to answer a reporter's questions about its policy on women, saying "We're a private club and we just really don't discuss it." However, a club member, who asked not to be identified, said that while there is no explicit prohibition on women, none has ever been admitted to membership. He said women guests are not allowed in the main dining room before 5 p.m.

During the hearing before the Senate Judiciary Committee, Silberman was also questioned by Simon and Sen. Mitch McConnell (R-Ky.) about his role at the Crocker National Bank of San Francisco, which was recently fined $2.25 million by the Treasury Department for failing to report cash transactions totaling $3.98 billion.

Silberman was an executive vice president and general counsel at Crocker between 1979 and 1982, including two years in which the bank failed to comply with a regulation, issued in June 1980, requiring U.S. banks to report to the Internal Revenue Service all cash transfers over $10,000 from foreign banks.

Yesterday, Silberman said he was not aware of the rule change, but added, "I feel a sense of responsibility. It happened on my watch."

He continued, "That change was missed at Crocker and maybe 60 other banks . It was not brought to my attention."

He sharply disputed Simon's suggestion that the bank's failure to report the cash transactions meant that it was assisting in "laundering" money from drug or crime sources.

At the hearing, Silberman was warmly praised by three Republican senators, McConnell, Bob Packwood (R-Ore.) and Pete Wilson (R-Calif.). Packwood recalled that Silberman served at the Justice Department during the Watergate affair, which forced the resignation of President Nixon in 1974.

"You can go through all the books and articles on Watergate and not find a sentence that ever taints Larry Silberman," Packwood declared. "He has always served fairly, honestly, and in the best interests of the United States."

Yesterday, before asking Silberman about the Metropolitan Club, Simon quoted a provision of the American Bar Association code of judicial conduct, adopted last year, which says it is "inappropriate" for judges to belong to any organization that practices "invidious discrimination on the basis of race, sex, religion, or national origin."

A 1981 resolution by the U.S. Judicial Conference, composed of federal judges, also says judges should not hold memberships in groups practicing "invidious discrimination" but does not define that phrase.

Simon said that since he joined the committee in January, the panel has not approved any judicial nominees belonging to single-sex clubs and at least three appointees resigned from such clubs to get confirmed.

Silberman said he will "go back to the code of ethics and seriously consider [Simon's] request. If I felt being a member of the club was against the canons, I would have no choice."