Mayor Marion Barry accused The Washington Post yesterday of singling out the District government for an investigation of minority contracting practices in an effort to embarrass the administration and destroy its program to promote minority-owned businesses.

Barry, citing requests made by the newspaper under the D.C. Freedom of Information Act for contract-related documents, said the inquiry was politically motivated and that "a lot of people don't want $158 million worth of contracts in the last year going to the minority business community."

"Why aren't they The Post in Fairfax County asking the same questions?" Barry said. "Why aren't they in Montgomery County asking the same questions? Why aren't they in Prince George's asking the same questions . . . . I am saying, why us? Why single out the District of Columbia government to ask all these voluminous questions if it is not to try to embarrass and discredit?"

The mayor said that he was told by a Post employe that the newspaper was out to "get" his administration.

Leonard Downie Jr., managing editor of The Post, denied that the newspaper was attempting to attack the mayor or the minority contracting program. He said The Post was "not putting the District under siege" and noted that the Barry administration had agreed last week to a schedule for releasing copies of documents to the newspaper.

"I am surprised . . . because a week ago Deputy Mayor Thomas Downs negotiated an agreement with us which provides for the orderly fulfillment of the Freedom of Information requests," Downie said. " . . . I can't understand why something Deputy Mayor Downs agreed to last week was so displeasing to the mayor."

Barry, fielding questions at his monthly press conference, also told reporters that he was not aware of any city workers who had contracted acquired immune deficiency syndrome, but added that he did not think workers suffering the disease should be forced to leave their jobs.

"Those persons who have AIDS . . . ought to continue working until they get sick and cannot work," said Barry, noting that AIDS cannot be transmitted through casual contact.

Barry declined to say whether he intended to veto the interstate banking bill passed by the D.C. City Council last week and said he was waiting to see if local banks could match an offer by Citicorp of $100 million in mortgage and business loans to local residents and businesses. The New York-based money-center bank could stand to gain by Barry's veto if subsequent interstate banking legislation includes a "trigger" provision allowing Citicorp to do business in the District in two years.

Barry criticized The Post for seeking documents related to the contracting program administered by the D.C. Minority Business Opportunity Commission (MBOC). The program, which sets aside at least 35 percent of the city's contracts for minority firms, presently includes 490 companies certified by MBOC, Barry said.

"We have received about 26 Freedom of Information requests, mostly from The Washington Post, wanting to know every minority contractor for 1983, 1984 and 1985," Barry said. "They are not asking for that kind of information to write a good story about how well our program is going. They are asking for that information to embarrass this administration and try to destroy our minority contracting program. That's why they are doing it."

The mayor said the requests would cost his administration $40,000 in workers' time and copying costs.

Downie said The Post "files lots of FOIA requests every year" with numerous local and federal government agencies. He denied the newspaper was singling out the District to the exclusion of other jurisdictions.

"It's our intent to hold all area governments accountable," he said.

The Post's inquiry into minority contracts, begun earlier this summer, follows newspaper reports and federal investigations over the last year and a half that have centered on problems with the city's procurement practices and the awarding of large contracts to minority firms.

In a series published in August 1984, The Post reported that the District routinely paid more than surrounding jursidictions for purchases of items under $10,000.

In addition, Jose Gutierrez, former director of the D.C. Department of Administrative Services, the city's chief purchasing agency, alleged last spring that some District contracts were given to political favorites of the Barry administration.

The House of Representatives voted this summer to require the District to submit all contracts to competitive bidding. The City Council subsequently scheduled action on a bill that would revamp the city's procurement practices.

Barry defended the minority contracting program as an effective tool to promote economic development within the minority community and to boost the District economy. He said he knew of no serious problems with the program but conceded minor mistakes may be uncovered in the documents requested by The Post.