The D. C. Court of Appeals yesterday upheld the authority of a private attorney to seek a court order for involuntary commitment of a person to the city's mental hospital if city government attorneys decline to pursue the case.

The three-judge appeals panel ruled in three cases in which parents sought to have their sons committed by the D. C. Superior Court to St. Elizabeths Hospital, based on a recommendation by the D. C. Commission on Mental Health.

In each case, however, the sons, represented by court-appointed attorneys from the city's Public Defender Service, demanded a court trial to contest the commitment recommendation. The D. C. Corporation Counsel's office decided not to take the cases, so private attorneys represented the families in court.

The Corporation Counsel's office can elect not to take such a case for a variety of reasons, including a shortage of attorneys to handle such matters.

Court officials estimate that 100 or more private actions for involuntary commitments, brought by spouses, parents, legal guardians and others, are brought each year. About 10 cases a year are contested at trial, the officials said.

The appeals court said the city's civil commitment laws leave room for private attorneys to take the cases, and dismissed the Public Defenders' arguments that only a "public attorney" could act impartially to screen out "frivolous or vindictive" requests for involuntary hospitalization.

The Mental Health Commission, the court and the jury provide the impartial safeguards needed to protect the constitutional rights of persons alleged to be mentally ill, the appeals court said in an opinion written by Judge John Ferren.

The court indicated that a mentally ill person might be denied needed treatment if a commitment case were dropped simply because the Corporation Counsel decided not to proceed with the case.

Judge Frank Q. Nebeker and Stanley S. Harris joined in the decision.