Winfred R. Mundle, general counsel of the D. C. Board of Elections and Ethics, has resigned effective June 30, he confirmed yesterday.

The resignation, which has been accepted, followed a period of growing tension between Mundle and members of the three-person board, and especially its chairwoman, Shari B. Kharasch.

Board members sometimes have complained that Mundle is slow in producing work that they said fails to meet their standards. Mundle in turn has complained of working in substandard quarters with too small a staff, and of being expected to produce politically acceptable opinions.

Mundle, 48, earns $47,500 a year. He has served as the principal lawyer for the board since January 1975 when it was creatd as part of the city's home rule government.

He has been a key figure in enforcing laws related to the conduct and financing of political campaigns and the ethical behavior of city officials.

His resignation will create a major vacancy little more than two months before a primary election Sept. 12 in which candidates for mayor and City Counsel seats are to be chosen. The general election is scheduled Nov. 7.

Mundle said his letter of resignation, which he submitted last week, contains no reason other than that he intends to return to private law practice. He said he was not asked to quit the job.

Kharasch confirmed the resignation, but would not discuss details. She said the board must work out arrangements for granting terminal leave to Mundle.

A native of South Carolina, Mundle was graduated from Howard University in 1950 and the Georgetown Law School in 1954. He was an investigator for the old D. C. welfare department before starting the full-time practice of law in 1962.