MOSCOW, MARCH 1 -- The Soviet Union announced today that new regulations protecting patients against arbitrary commitment to mental hospitals are now in effect.

Human rights groups in the West and the Soviet Union have long contended that Moscow has confined political dissidents in psychiatric hospitals. In January the government said the criminal code would make the "illegal commitment of a patently healthy person to a mental hospital a criminal offense."

The new laws, which Dr. Marat Vartanyan, head of the All-Union Center for Mental Health, said took effect today, give relatives of committed patients the right to appeal in court against doctors' decisions.

"As far as the outcry around Soviet psychiatry in the West is concerned," Vartanyan told Tass, " . . . this propaganda farce is motivated by political considerations and is of a provocative character."

Last year the Kremlin pardoned 180 political prisoners from labor camps and jails, but sources here said that some dissidents remain in psychiatric hospitals as prisoners.

Vartanyan said the Soviet Union is appointing chief psychiatrists of republics, regions and cities as court officials to whom patients and their relatives may file complaints.

Human rights activist Sergei Grigoryants said in an interview that the new laws will have little meaning "unless there is a real outside mechanism to watch over them."