Court proceedings that could lead to the disbarment of former Maryland governor Marvin Mandel began yesterday in Baltimore with the state Attorney Grievance Commission arguing that Mandel's convictions for racketeering and mail fraud were offenses of moral turpitude.

Mandel, who spent 19 months in federal prison before President Reagan commuted his three-year sentence last December, has been under interim suspension from the bar since Dec. 1, 1977. Under state law, an attorney convicted of a crime must go through a "further proceeding" hearing after incarceration to determine if he should be reprimanded, suspended or disbarred.

The former two-term governor, and his wife, Jeanne, listened in Circuit Court yesterday as Mandel's attorneys, Arnold Weiner and Albert Figinski, requested a second hearing, which Judge J. Harold Grady set for March 16, at which they said witnesses would testify to Mandel's integrity during his years in private law practice. Weiner argued that the moral turpitude charge was "grossly inappropriate."

Melvin Hirshman, counsel for the grievance commission, said, "We have already submitted a finding of fact which points out that under the law a criminal conviction is final and in two other cases mail fraud has been ruled an act of moral turpitude."

Weiner said Mandel's defense would be based on the tie vote by which Mandel's conviction was upheld by the 4th U.S. Circuit Court of Appeals. "Under the rules that vote is not a final judgment for anything proceeding outside of the case itself," Weiner said.

Under Maryland law, an attorney found guilty of moral turpitude faces disbarment by the Court of Appeals. Hirshman would not comment on what recommendation his office would make.

Judge Grady will submit a finding of fact to the Court of Appeals, which will make a final decision on what disciplinary action, if any, it should take against Mandel.