Now in their fourth month of negotiating with a union representing 150 Harvard employees, University officials have requested an independent mediator to speed up contract talks.

The Harvard Security Guards, Parking Attendants and Fogg Museum Guards Union has been without a contract since 1996, when they decided to separate from their umbrella organization, the local 254th of the Service Employees International Union.

The request for a mediator marks the second time that one of the two sides has sought outside help to end their dispute.

Harvard Spokesperson Joe Wrinn said University officials are attempting to come to an agreement with the union.

"It's in everybody's interests to do what is necessary to resolve the situation," Wrinn said.

But sources said talks over a new contract have been stymied by arguments over specific issues, including a retirement package for older members of the union. Benefits are also a sticking point, according to another source.

Some union members say the University is unwilling to sign a new contract with the guards, noting that several Harvard schools have out-sourced security operations in recent years to companies that provide more guards at a lesser cost.

In early November, both sides agreed to a mediator, saying contract talks had deadlocked over key issues.

But just days later, talks resumed without outside help.

At the time, Harvard's Director of Labor Relations Kim A. Roberts '78 called the November meetings "productive," and union vice president Robert V. Travers said they "went very well."

However, signs of progress quickly disappeared, as both sides cancelled meetings scheduled for December and January.

Although the two sides said the cancellations had been due to scheduling conflicts, no official meetings were rescheduled until an informal meeting late last month.

One of these sessions, tentatively scheduledfor Feb. 29, has been cancelled, said a sourcewith knowledge of the talks.

No new guards have been hired since 1990, andattrition and retirement have reduced the numberof guards employed from an all-time high of 106 in1993 to less than 60 now.

When negotiations began anew last November, afive-person panel led by Union President StephenG. McCombe initiated discussion with Roberts.

Both McCombe and Roberts declined to commentyesterday, citing an agreement not to talk tomedia.