The Pan American Ball at the Organization of American States could have been a solemn affair, with the threat of confrontation between Argentina and Britain hitting close to the native home of many of the guests.

But the dyed-in-the-wool Washington partygoers who attended the ball Saturday night wouldn't permit it.

"It's much too late in the day for thinking about war in Argentina," said Alejandro Orfila, the Argentine secretary general of the OAS, soon after striding into the Hall of the Americas alone; his wife went to their country home for the Easter weekend. He moved around the rooms greeting friends not with a handshake but usually with a big grin, a hug and a kiss for each cheek.

"As you know," said Kenneth M. Crosby, ball chairman and former FBI agent, "in Washington the problems come and go, but the festivities, the balls, the parties are always with us."

How right he was.

And this particular Washington party was the proof. No one wanted to talk problems.

"It's a social affair--mostly chitchat," said Mayor Marion Barry, as he stood by the long tables filled with fruit chunks ready to be dipped in warm, melted chocolate. "No one wants to get too heavy into anything."

And, as with any top-notch Washington party, the usual black ties and long gowns were out in full force, dressing ambassadors from many Latin and South American embassies. The tab, $150 each for dinner and the ball, went to the Pan American Development Foundation, a nonprofit organization formed to stimulate private sector development in Latin America and the Caribbean.

"Tonight's been a great success, just a great success," said Val T. McComie, deputy secretary general of the OAS, after finding out $60,000 was raised from the evening's ticket sales. "I was surprised so many people came, especially since it's Holy Saturday."

Beginning at 7 p.m. the 450 guests split up to dine at 22 ambassadors' residences. After dinner they met in the grand marble foyer of the hall, greeted by a group of young violinists who turned the spotlight over to the Original Trinidad and Tobago Steel Band, which played a march written by J. William Middendorf, U.S. ambassador to the OAS.

A receiving line upstairs from the hall, which included Edward Marasciulo, executive vice president of the PADF, the McComies, the Barrys and Argentine Ambassador to the OAS and Mrs. Raul Quijano, led people into a ballroom where the Howard Devron Band combo provided music to cha-cha by.

One guest, however, was not quite a part of the night's festive air.

"I am sad to be here," said Cmdr. Eduardo Alimonda, the assistant naval attache' from Argentina, with a shrug and a weary smile. "I would like to be in my country, but my job is here," he said, before turning to enter the spacious ballroom for the door prize drawings.

For the most part, however, optimistic Washingtonians reigned.

"I see the OAS ambassador of Argentina talking to people and it's a good sign," said John J. Jova, former U.S. ambassador to Honduras and Mexico, who served as a jovial master of ceremonies for the program. "The more dialogue the better. Of course, he's not talking to a Brit, but . . . "

Regardless of major world upheavals and holidays, the Pan American Ball was destined to be a success due to Mayor Barry, who said, "I've declared this week Pan American Week in the District . . . "