D.C. Police Chief Burtell M. Jefferson, following complaints by gay and civil rights groups, has issued a special call for enforcement of a law barring restaurants and taverns from demanding advance identification of would-be patrons.

Requiring such identification, a practice known as "carding," has allegedly been used to bar blacks and homosexuals from some establishments.

The question of discrimination at nightclubs here received widespread public attention following publication of an article earlier this year in The Washington Post.

Business owners cited for "carding," could be fined up to $50 for each offense. If the city's human rights office finds that discrimination has occurred, the business could be stripped of its liquor license.

Several clubs that have restricted admittance for various reasons are under investigation by the human rights office and five clubs already have been charged by the office with discriminating against blacks. Methods of restriction vary, but basically consist of demands for more items of identification than a prospective patron can produce.

Jefferson's order, issued to city police Nov. 2, was announced at a news conference yesterday by representatives of the Gay Activists Alliance and the D.C. Coalition of Black Lesbian Women and Gay Men.

"Carding has been described as an effort to prevent serving of alcoholic beverages to persons not of legal age. Jefferson said liquor by the drink can be served only where food also is served and "any person is obviously of age to purchase food." By law, he added, serving drinks can only be incidental to serving food, and thus no pre-entry identification can be required for admission to any place open to the general public.