Faced with the prospect of countless invitations to diplomatic events and courtesy calls by foreign dignitaries, Mayor Marion Barry plans to set up a new protocol office in the District of Columbia government, a top aide said yesterday.

Dwight Cropp, Barry's executive secretary, said the city will ask the State Department to help establish the office.He said it does not have a high priority for early action.

Cropp disclosed the plan after Roel Karamat, ambassador from the South American nation of Surinam, paid the first courtesy call by a foreign diplomat on the new mayor. Surinam is the former colony of Dutch Guiana.

During the visit, Cropp said, the envoy promised Barry that embassy employes would abide by all traffic and other laws of the District.

In discussing the planned protocol office, Cropp said the mayor hopes to use it in developing contacts with embassies that may steer foreign economic investment into the city. Such an idea was advanced during last year's mayoral campaign by Republican candidate Arthur A. Fletcher.

Martin K. Schaller, who served as executive secretary and protocol officer for former mayor Walter E. Washington, said the mayor routinely receives about 250 invitations each year to embassy events. He said there are at least two diplomatically sponsored foreign callers a week at city hall although not all see the mayor.

Although Walter Washington enjoyed diplomatic events, he actually attended relatively few, sending Schaller in his place, the former executive secretary said.

Most events attended by the former mayor were in honor of monarchs, presidents and prime ministers, Schaller said. He said ambassadors newly assigned to Washington routinely pay a courtesy call on the mayor soon after arriving.

Barry, in an interview shortly before taking office, said he was "not going to be out at all these functions, burning up my energies... I don't intend to be burned out in eight years -- I'll be 50 years old, and I still want to be active and moving."