A mediation session between Harvard and the Patrolman's Association, the union for the University's police force, earlier this month was broken off when Harvard negotiators charged that the union had introduced "new issues" into the dispute, a source close to the negotiations said Tuesday.

The University's position is that since the dispute is now in mediation--a state mediator has been called in--the only question that should be considered is the size of a salary increase in the contract being negotiated, the source said.

When union representatives insisted that other questions such as fringe benefits and vacations also be discussed, the source said, Harvard negotiators left the meeting.

No New Issues

The union's lawyer, Henry Wise, confirmed Tuesday that the September 8 session had been broken off, but denied that the issues the union introduced were new ones.

Wise said that all union demands had been detailed in a letter to President Bok and the Fellows of Harvard College dated June 3, and said the demands "have never been withdrawn."

Edward W. Powers, Harvard's director of employee relations and the University's chief labor negotiator, would not comment yesterday on the negotiating session except to say, "little progress was made." Powers said a new session is scheduled for September 19, adding, "Given the skill of the mediator, I am hopeful."

In addition to procedural disputes, the University and the union are very far apart on the question of salary, Wise said.

Harvard is offering the police an increase of 9.6 per cent while the union is demanding a raise "greater than the 21-per-cent rise in the cost of living over the last two vears." Wise said.

The Patrolman's Association has also insisted that the University attempt to establish some sort of parity between Harvard salaries and those of the far-better paid Cambridge police.

Harvard has refused to consider Cambridge police salaries as an issue.