A Pennsylvania congressman is leading an effort by some House Democrats for the removal of indicted Rep. Charles C. Diggs (D-Mich.) as chairman of the House District Committee and the African subcommittee of the International Relations Committee.

Rep. Peter H. Kostmayer said last night that he would decide within the next few days whether to ask the House Democratic Caucus to strip Diggs of the two chairmanships or seek help in pressuring Diggs to resign voluntarily.

Kostmayer and Rep. Andrew Maguire (D-N.J.) forced a meeting Monday between Diggs and House Speaker Thomas P. (Tip) O'Neil, during which Diggs told O'Neil he would not step aside.

There is support for the idea that an indicted member should not continue in a leadership position. But it appeared unlikely that many members would be willing, as Rep. Berkley Bedell (D-Iowa) put it, "to decide that in the middle of the game."

Bedell and Maguire both said they talked to Diggs yesterday about a voluntary resignation. But Bedell said "he says he's not guilty and that there's no precedent to require anyone to step aside unless convicted."

Bedell said he would favor changing the rules when the Democrats organize the 96th Congress next January, but "he (Diggs) seems to have a legitimate argument" not to strip him of his offices now.

Kostmayer, a 32-year-old former newspaper reporter who represents suburban Philadelphia, said that while his actions "in no way express a judgment with regard to Mr. Diggs' innocence or guilt," he believes Diggs will need a lot of time to defend himself against the 35-count indictment.

"Chairmanship is a privilege granted by the caucus to the more senior and experienced members of our party," Kostmayer said in a draft letter that he showed to O'Neil in urging a meeting between the speaker and Diggs.

Chairmen are selected, Kostmayer went on, "after some evaluation is made concerning the quality of the performance and distinction of service . . . Therefore, when questions are raised by as serious a legal instrument as an indictment, then until the cloud of doubt is removed, it seems in the best interest of the Congress and its good name to have the chairman involved voluntarily removed himself."

In the absence of a voluntary action, Kostmayer said, rules of the caucus permit any 50 members to force a vote by the entire 288-member Democratic delegation on a question.

Rep. Parren Mitchell (D-Md.), chairman of the Black Caucus, said he would be "bitterly opposed" to any move to strip Diggs of his chairmanship. "If he wants to step down voluntarily, that's fine, but any other move would fly in the face of precedent."

Mitchell said that he doesn't see any racial overtones in the move, but "everybody else would. It would be establishing a precedent on a black member."

Rep. Herbert E. Harris II (D-Va.), a member of the District Committee, said "a speedy trial is the best way to resolve the question." Harris said he saw no need for "interim action."

The second-ranking member of the District Committee, Rep. Ronald V. Dellums (D-Calif.), has "pretty much taken up the day-to-day operation of the committee," Harris said.

Dellums, another member of the Black Caucus, has refrained from comment on the indictment. But an aide denied that Dellums had stepped up his activities on the District Committee. "That's not his style," the aide said.

Another District Committee member, Rep. Newton I. Steers (R-Md.) noted that as a Republican he has no voice in the matter. But he added that "on principle, he is presumed innocent. To strip him of his chairmanship would be incompatible with that presumption."

Maguire said he is "not certain it wouuld succeed or make sense" to try to force Diggs out. But he added that the charges "relate to conduct of the public's business, and that's very difficult to ignore. We need an interim way of dealing with these situations."

Asked if he thought it would be possible to pressure Diggs into resigning, Maguire said, "Today I felt he really listened to what I was saying."

Pressure from colleagues led to the resignation of Rep. Wayne Hays (D-Ohio) in 1976, first as the powerful chairman of the House Administration Committee and later from his seat in Congress. Hays was embroiled in a sex scandal with one of his employes, Elizabeth Ray.

Diggs, a 55-year-old, 12-term representative of Detroit's inner city, was indicted March 23 on charges that he diverted about $101,000 in government payroll money for his personal use. He entered a plea of innocent at arraignment last week in U.S. District Court here.