Convicted Rep. Charles Diggs (D-Mich.) will not seek reelection as chairman of the Africa subcommittee of the House International Relations Committee, sources close to the Democratic leadership confirmed last night.

It is also believed that Diggs, who is appealing a three-year sentence for taking salary kickbacks from his staff, discussed abstaining from voting while his appeals are underway and resigning if his appeals fail, during an hour-long meeting late yesterday afternoon with House Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.), Majority Whip John Brademas (D-Ind.), Democratic Caucus Chairman Tom Foley (D-Wash.) and Rep. Benjamin Rosenthal (D-N.Y.).

Those at the meeting refused to discuss what was decided and would not confirm that voting and resignation were discussed. Diggs was not immediately available for comment.

However, it is known that conversations on the issues of Diggs' participation in voting and what to do about moves to expel him have been going on among Democratic leaders for some time.

Last week Majority Leader Jim Wright (D-Tex.) confirmed that conversations were going on about whether Diggs should continue to vote in the House while his appeals are pending.

Democrats must face that issue this week, when a proposal by Rep. Peter Kostmayer (D-Pa.) comes up in the Democratic Caucus. The proposal would require a convicted member to abstain from voting and participating in committee business until he or she has completed any prison sentence and paid all fines.

Present House rules say a member should abstain from voting or participating in committee business until he or she has been cleared or reelected. Diggs was reelected in November following his conviction in October.

Kostmayer also has a proposal before the caucus calling for an automatic vote on expulsion of any member convicted of a crime for which a sentence of two or more years has been imposed, once the conviction is final.

Republicans are gathering signatures on a complaint to the ethics committee, asking it to investigate possible grounds for expulsion of Diggs once his appeals are exhausted.

Although the Congressional Black Caucus has vowed to fight any expulsion move against Diggs, and although Wright has publicly stated Diggs should not be expelled even if his conviction is upheld, the prospect of a convicted felon voting in the House or drawing a salary while serving a jail sentence is potentially embarrassing for the Democrats.

Diggs had already announced he would not seek reelection as chairman of the House District of Columbia Committee, which he headed in the last Congress. But until yesterday, he was trying to retain the chairmanship of the Africa subcommittee.

However, in December the Democratic Caucus voted to require convicted subcommittee chairmen to be voted on by the full caucus, if they were renominated and reelected to the post by the committee on which they served.

The chances that Diggs could have been reelected African affairs subcommittee chairman were slim. Rep. Dante Fascell (D-Fla.) a high-ranking member of the International Relations Committee, said yesterday before the Diggs meeting with the leadership that he "doubted very much" that the committee would renominate Diggs for the post.