District government officials canceled a major contract yesterday with Decision Information Systems Corp. to provide drug counseling to public school students amid allegations that the month-old contract was improperly awarded and managed.

David Rivers, director of the Department of Human Services, said DISC Chairman John Clyburn asked for permission to withdraw from the $671,220 contract because "a negative atmosphere" created by "unfounded allegations . . . would make it very difficult for him" and the city to continue managing the contract.

Rivers said at a news conference that the criticism of the contract by D.C. City Council Chairman David A. Clarke and members of the school board was "unfair" and levied by "a few politicians."

Those officials said earlier this week they were concerned about allowing Clyburn, who was with Joann Medina, who died of a drug overdose in December 1983, for the 12 hours preceding her collapse, to oversee a drug counseling program in the public schools.

Clarke stepped up his criticism of the contract yesterday, saying that DHS evaluators had given two of DISC's competitors worse scores than DISC on the cost of their proposals, although the firms were offering to do the work for less money.

According to Clarke, the DHS evaluators' scores differed sharply from those of the third member of a city evaluation team, an employe of D.C. schools. "It doesn't make sense to me," he said.

Clarke also criticized the fact that DHS officials asked evaluators to judge DISC's proposal against only partial bids from other firms, which he said "is like comparing apples and oranges." Clarke said he asked D.C. Auditor Otis Troupe yesterday to investigate how the contract was awarded.

One DHS official, who asked not be named, also raised questions about a $37,201 initial payment to DISC, approved on April 9. According to Robert Allison, DHS's deputy controller, DHS officials approved payment of a DISC voucher for services provided from March 10 to April 4, although the contract was not negotiated until March 14 and not officially awarded until March 24.

Clyburn said DISC began work on March 10 based on an oral go-ahead from Vallie Byrdsong, DHS' contracting officer. Byrdsong said he told DISC officials orally to begin work sometime after March 14.

The Washington Times reported yesterday that five tax liens totaling $252,330 are on file at the D.C. Recorder of Deeds office against the Granville Corp., which changed its name last year to DISC.

According to records, the firm owes $162,744 in federal income taxes from 1982 and 1983, $31,648 in federal employe withholding tax and $56,593 in District taxes.

Those tax liens were not considered during the evaluation process, according to DHS officials, although contracting officials acknowledged that such liens generally raise questions about whether a contractor has the financial wherewithal to pay employes and provide services under contract.

Byrdsong said yesterday that DHS sometimes asks contractors to attest to the fact that they face no tax liens in their proposals, but did not request the information in this case. Byrdsong said, "There wasn't any conscious effort not to put it in there."

Twelve firms submitted bids for the contract and evaluation sheets show all of them were considered, though officials of one firm have charged their bid was not opened.

The decision to cancel the contract came one day after a D.C. Board of Education committee voted to refuse to accept the services of DISC and two other contractors who won related contracts. School board member R. Calvin Lockridge (Ward 8), a committee member, argued that Clyburn was morally unfit to lead a drug prevention effort.

Lockridge also charged in an interview that a similar drug-counseling program run by DISC last summer was "a disaster." Rivers has said DISC's program achieved its goals, but school officials said yesterday that the program did not reach all the students who were supposed to be trained in alcohol and drug counseling.

The controversy reflects in part the growing assertiveness of the school board in the city's contracting process and the feeling on the part of some board members that agency officials under Mayor Marion Barry play favorites in awarding contracts.

Meanwhile, Clyburn filed a $25 million libel suit yesterday in U.S. District Court against The Washington Times in connection with the paper's recent stories about him that linked the DISC drug counseling contract with the Medina incident.

The suit said Clyburn "immediately attempted to revive her Medina , then promptly arranged for an ambulance to be called" when he found her unconscious. Clyburn has previously said he called for an ambulance, but the suit said "a female friend who was also present in the apartment at the time" made the call.