John W. Hinckley Jr., accused of the attempted assassination of President Reagan last March 30, has been examined by a team of three psychiatrists and a psychologist selected by government prosecutors. The panel includes a doctor who examined Arthur H. Bremer, the convicted assailant of former Alabama Gov. George C. Wallace, and one who tested Chicago mass murderer John Wayne Gacy.

Defense lawyers for Hinckley in Washington reportedly have consulted with a group of doctors who, like the government's team, would examine Hinckley to determine whether he is competent to stand trial and was responsible for his acts last March 30.

These issues are critical if Hinckley's lawyers raise an insanity defense or contend that his mental capacity was so diminished at the time of the shooting that he should not be held responsible for his acts.

Hinckley's lawyer, Vincent J. Fuller, repeatedly has refused to respond to questions about the case.

The team of doctors assembled by the government is expected to submit a report to the prosecution of their evaluation of Hinckley's mental state now and at the time of the shooting. Those doctors would be expected to testify for the government if Hinckley is brought to trial and invokes an insanity defense or other contentions involving his degree of responsibility.

Hinckley is being held at the federal correctional institution at Butner, N.C., under a court order that expires -- but could be extended -- on July 2. He has been undergoing psychiatric tests since shortly after the shooting incident.

Among the psychiatrists who have examined Hinckley for the government is Jonas Rappeport, a well-known forensic psychiatrist who examined Bremer and Sara Jane Moore, who pleaded guilty to the attempted assassination of former president Gerald R. Ford.

Rappeport regularly works with the criminal court system in Baltimore. Hinckley also has been examined for the government within the last two months by psychiatrists Parke Elliot Dietz, who runs the Institute for Law and Psychiatry at the Harvard Medical School, and James Cavanaugh of Chicago, who examined Gacy.

Cavanaugh is associated with the Isaac Ray Center at the Rush-Presbyterian Hospital Center in Chicago, where he heads a team of psychiatrists, psychologists and lawyers who participate in court cases.

At the request of the government Hinckley also has been examined by John Monahan, a psychologist who is a member of the faculty of the prestigious University of Virginia law school.