Soviet President Leonid Brezhnev bantered affably with the presidents of Bangladesh and Panama. West German Chancellor Helmut Schmidt and Chinese Chairman Hua Guofeng chatted about Pakistan's problems. Bulgarian President Todor Zhivkov embraced friends.

While they waited for President Tito's funeral procession to get under way today, leaders of the world's big and small nations passed the time as anyone else would, making small talk about topics of interest and greeting old acquaintances.

For the most part, high-level diplomacy was conducted in secrecy in embassies and hotel rooms, well away from the roving lenses of television cameras. Nevertheless, this reporter found it possible, simply by straying from his designated bleacher, to eavesdrop on and chat with more presidents and foreign ministers in the space of 30 minutes than one would expect to meet in a lifetime.

Apparently, conversations among the mighty were so low key that Iranian Foreign Minister Sadegh Ghotbzadeh almost got through the day without hearing a word about American hostages.

After the funeral procession had moved off, and delegations withdrew to the nearby parliament building for refreshments, a reporter found Ghotbzadeh sitting in a corner of the cafeteria.

Asked whether the issue of the American hostages in Iran had come up in Belgrade, the Iranian groaned: "This is the first time in many weeks that I have spent a day without thinking about that problem at all. You have just ruined it."

Outside the green-domed parliament building, where Tito's body had been lying in state since Monday evening, the world's leaders greeted each other in the sunshine as they waited for the five-hour ceremonies to begin.

As Vice President Mondale arrived, surrounded by a phalanx of Secret Service men, diplomatic gossip centered on Chairman Hua and West German Chancellor Schmidt. The two men chanced into one another and filled in time by discussing some of the implications of the crisis in Afghanistan.

Schmidt was heard saying in English that his country was giving big financial support to Pakistan, but expressing concern about the internal instability of the government of President Mohammed Zia ul-Haq. He asked Chairman Hua for his opinion, aware that the Pakistani leader had just been in Peking for talks.

Through an interpreter, Chairman Hua replied that he felt optimistic as long as the region was able to rely on assistance from outside. It was not clear whether he was referring primarily to Afghanistan or Pakistan. The conversation then turned to internal developments in China and tailed off in pleasantries with Hua apologizing for not being able to speak English.

Next to approach Schmidt, clearly one of the most sought-after leaders, was Bulgaria's veteran president, Zhivkov, the Kremlin's staunchest ally. He beamed happily as Schmidt told him it was very important that countries such as West Germany and Bulgaria not get drawn into the conflicts of the great powers.

Chairman Hua, meanwhile, was telling a reporter how he had been able to meet with Japanese Prime Minister Masayoshi Ohira, Indian Prime Minister Indira Gandhi and Yasser Arafat of the Palestine Liberation Organization.The talks had been very useful, he said, and Afghanistan had been among the important subjects discussed. "No, I have no plans to meet Mr. Brezhnev," Hua added firmly, as President Ahmed Sekou Toure of Guinea came up to embrace him warmly.

In another corner of the podium, Polish leader Edward Gierek welcomed the opportunity to talk about the 25th anniversary of the Warsaw Pact to be held in Warsaw next week. He said the summit, which will be attended by the entire Soviet Bloc leadership, would publish a communique of the utmost importance with some surprises. "I advise you to read it carefully," he added.

At that point, the Soviet party arrived in a six-door Mercedes that once belonged to Tito. Brezhnev came out, escorted by Foreign Minister Andrei Gromyko, a corpulent Red Army general wearing a huge hat and several jovial KGB secret police agents. Looking tanned from a recent vacation and comparatively fit, he walked to the place of honor at the front of the platform. He embraced Benjedid Chadli of Algeria and exchanged small talk with a succession of presidents.

President Ziaur Rahman of Bangladesh approached the 73-year-old Kremlin leader to thank him for "his work for peace." Brezhnev shrugged modestly, saying, "We try our hardest," adding later: "I am ready for anything in the struggle for peace."

To a mumbled comment from President Aristides Royo of Panama, Brezhnev replied, laughing: "I have nothing against the Americans." The Panamanian leader thanked him for all his support over the Panama Canal, "which is now free." Brezhnev remarked: "Yes, we have exactly the same opinion on that subject."

After parliament, the next best place for gathering information on diplomatic summitry was the slow-working elevators of the ultramodern Intercotinental Hotel, where most of the leaders were staying. A reporter could stand in front of them and watch world statesmen being absorbed or disgorged. If they looked at all interesting, he could take a ride with them as well.

When asked politely, the familiar looking face with the sleekly groomed hair and the twirled moustache agreed that yes, he was President Zia of Pakistan. He had just received a letter from President Brezhnev, outlining the Soviet view of events in Afghanistan. By the time the elevator reached his floor, he divulged that he would be meeting Gandhi.

On the elevator down, the doors opened -- and there was President Kenneth Kaunda of Zambia. Confusion followed as the elevator refused to take any more passengers, sounding its overweight alarm, much to the amusement of Zambian officials who had to evacuate it.

Lillian Carter dropped by to pay a courtesy call on Gandhi, who earlier had met Tito's widow Jovanka. And so it went on; a curious, but somehow fitting tribute to a unique politician who was able to overcome the divisions between East and West.