Marios G. Michaelides, accused of the 1975 murder of his wife, the daughter of the late diplomat David K.E. Bruce, protested his innocence yesterday and accused the Bruce family of trying to discredit him, a Greek newspaper reported.

Michaelides, 33, a fruit exporter in Athens, was quoted in the daily Acropolis, Athens' largest morning paper, as calling the Bruce family "very rich and politically powerful."

"I am innocent, and here, where the influence of the Bruces has not strength, my country's justice will prove my innocence," the paper reported him as saying.

Under in unusual provision of a Greek law Greek citizens can be charged in their native land with offenses committed in other countries. Michaelides is being investigated by Greek authorities for offenses similar to those filed earlier this year by a grand jury in Southside Virginia.

Michaelides was indicted by a Charlotte County, Va. grand jury last month for murder in the death of Alexandra Bruce Michaelides, who was found Nov. 7, 1975, on the grounds of the Bruce family estate, Staunton Hill Farm, with a single gunshot wound in the head.

Mrs. Michaelides, 29, died 36 hours later in Lynohburg General Hospital. Her death was ruled a suicide a week later, but the local prosecutor reopened the investigation into her death this year based on evidence supplied by Downey Rice, a Washington lawyer and former FBI and Senate investigator. Rice, who was hired by some family members, has declined to discuss the case.

Michaelides also was indicted for bigamy and grand larceny by the Charlotte County grand jury. He also denied those charges yesterday, the Athens newspaper said.

"They accused me of bigamy, but I have documents showing that my first marriage was legally dissolved," he was quoted as saying. "Alexandra Bruce knew all about it. She also knew my first wife, with whom she met repeatedly."

Meanwhile, it was learned that Mrs. Michaelides' will, written a month before the two were married in a Virginia civil ceremony in August 1975, named Michaelides as executor and beneficiary of her entire estate. But the will specified that he was neither to be the executor nor to receive anything unless they married. Court records show they were married Aug. 8, 1975, a court clerk said.

Michaelides was quoted by the Athens paper as saying he had relinquished his role in the will, which named his brother Eugene, of Athens, as executor in the event that Michaelides was unable to serve.

The will, which was filed for probate in December 1975 in Charlotte County, apparently has not received a final accounting, according to court clerk Stuart B. Fallen.

The newspaper also quoted Michaelides as saying that the Bruce family had tried to discredit him because he knew family secrets, which he refused to discuss with the newspaper.

Commonwealth's Attorney Edwin B. Baker, who was ordered Tuesday by Judge J. R. Snoddy to refrain from discussing the case, declined to comment on the Athens newspaper interview.