D.C. Corporation Counsel John R. Risher Jr., in a long, detailed report to the city's Office of Human Rights, has strongly denied charges that his office has discriminated against blacks and women in hiring and promotion.

In a memorandum to James W. Baldwin, director of the Human Rights Office, Risher said the report shows that the number of black attorneys employed as assistant corporation counsels "substantially exceeds" proportionately the number of black attorneys admitted to the D.C. Bar and that black female attorneys in Risher's office have the "best chance" of promotion.

The report was prepared in response to a complaint filed in May 1977 with the Human Rights office by black newspaper publisher and longtime community activist Calvin W. Rolark.

Rolark's complaint was filed a month after The Washington Post disclosed that the number of blacks who were assistant corporation counsel dropped during Risher's first year in office.

At the time, Rolark said he was concerned that there had been little improvement in hiring blacks as assistant corporation counsel since 1974, when the city was granted limited home rule. Rolark said yesterday he has not had a chance to read the report, released by Risher's office Monday.

Figures in the report show that four of the five black attorneys named assistant corporation counsel between June 1976 and December 1977 were appointed within the three months following the filing of Rolark's complaint. Three of the four were black women, according to the report.

Risher's office said he was out of town and not available for comment yesterday. As a result, it could not be determined whether any of the black attorneys hired after May 1977 had been under consideration before the filing of Rolark's complaint.

Between June 1976 and April 1977, 19 lawyers were hired an assistant corporation counsels, one of whom was black and another of Spanish descent, according to the report.

The report, in a footnote, acknowledges the accelerated hiring of black and female employes in the last six months of 1977. Though hirings were restricted in mid-1977 because of budget constraints, the report said, when the fiscal problem was eventually resolved, "black and female hiring increase dramatically."

The report was prepared for Risher by Geoffrey M. Alprin, deputy corporation counsel in charge of the criminal division; administrative officer Gloria Powell, and Pollie A. Harris, equal employment opportunity officer in the corporation counsel's office. The report covers the period from March 1976 to December 1977.

As for promotions, the report said for period 11 percent of the attorneys promoted were black. Just under 16 percent of all attorneys in the corporation counsel's office were black at the time. In December 1977, when 19 percent of the office attorney's were black, 25 percent of all promotions went to black lawyers. The report called te differences between the rate of promotion and representation "minimal."

For the period, women attorneys were promoted at a rate 25 percent higher than that for all attorneys in the office, the report said. According to the report, in December 1977, 18 of 95 attorneys in the office were women and 18 were black (at least four of the blacks were women).

Overall, black males had a "poorer chance" of promotion than any other class of employe, the report said. Black females had the highest chance.