The presiding judge in the upcoming retrial of Maryland Gov. Marvin Mandel has barred government prosecutors from examining portions of Mandel's 1974 divorce records because they are irrelevant to the case.

In an order issued early this week, U.S. District Judge Robert L. Taylor said that prosecutors had subpoenaed the records under the "erroneous belief" that the divorce file contained relevant information that they had not seen.

The retrial of the governor and his five codefendants on charges of mail fraud and racketeering is scheduled to begin April 13.

During the 1975 investigation of the political corruption case, the prosecutors' attention at one time focused on the Mandel divorce, which reportedly left the governor stippel of many of his financial assts.

Just before the grand jury in the case issued indictments in November, 1975, defense attorneys in the case agreed to allow prosecutors to examine the financial records pertaining to the divorce.

During their examination of documents at that time, prosecutors said in a memorandum filed on March 11, that they found that "portions of that one document make clear that there are other aspects of the financial relationship between . . . Mandel and his former wife which are not disclosed therein."

However, Judge Taylor's order emphasized that "the only relevant information to which the government is entitled is contained in (eight) paragraphs of the separation and property settlement agreement," which prosecutors already have apparently seen.

The prosecutors are thus left to look elsewhere for whatever divorse-related financial information they are seeking. Prosecutors contacted yesterday would not say whether they intend to fil any new subpoenas in the three weeks remaining before the trial begins.

A mis trial was declared in the original trial, they decided early this month to subpoena the divorse records.

Since the mistrial was declared, Irvin Kovens, a defendant in the case who was several from the first trial for health reasons, has been adjusted fit to stand trial with Mandel and the other defendants in April.

Only a few independently-revealed details of the divorce settlement have been reported during the more than two years since the divorce first became final, but Mandel himself has said in an interview that during his divorce from Barbara Mandel his life savings were whittled from $78,000 to $5,000.

It has been reported that Mandel received a $50,000 loan from Koveens, a powerful behind-the scenes figure in Baltimore politics, to help him defray the cost of the divorce.

The thrust of the prosecution's case against Mandel, as presented in the first trial, is that the governor's five codefendants - Kovens, and businessmen W. Dale Hesss, Ernest N. Cory and Brothers Harry and William Rodgers - gave the governor loans, jewelry and vacations in return for his manipulation of legislation to benefit a race track that the businessmen secretly owned.

Little evidence relating to the divorce was presented during last fall's trial.