D.C. Council member John Ray (D-At Large) and representatives of the Metropolitan Washington Committee on AIDS filed suit yesterday to block a proposed referendum on the recent AIDS insurance legislation passed by the D.C. Council.

The city legislation, passed in May, prohibits insurers from denying health, life or disability insurance coverage to persons on the basis of a positive test for exposure to the AIDS virus. Insurance companies could not charge such persons higher premiums for five years.

The law would not protect those who already have acquired immune deficiency syndrome.

Opponents and proponents of the measure are working against an Aug. 6 deadline, the expected last day of a congressional review period. The AIDS insurance law will go into effect after that unless opponents can persuade Congress to overturn it, which is an unlikely prospect, or unless they can get about 13,000 voters to petition for the referendum.

The D.C. Board of Elections and Ethics ruled on July 7 that the proposal to overturn the new law was a proper subject for a referendum. Yesterday was the last day challengers could file a court appeal.

The appeal, filed in D.C. Superior Court, said it was not a proper subject, because if the legislation is overturned, discrimination prohibited under other District laws would be authorized.