While President Reagan contemplates the crisis in the Middle East and what to do about the Soviet gas pipeline, another international dilemma affecting millions of Americans and as many dollars in business will be on the president's agenda: whether copies of Pac-Man games should be allowed to enter the country.

Last week the International Trade Commission unanimously decided that an influx of foreign copies of the popular Pac-Man games--manufactured by Midway Manufacturing Co. of Chicago, which bought the rights to the game from the originator, Namco Ltd. of Japan--has violated trademark and copyright infringement laws and will be excluded from entry into the United States. President Reagan must decide within the next two months whether to go along with that decision or let the fakes in.

Midway had filed a complaint of unfair trading practices mainly against Japanese and Taiwanese firms that allegedly gained illegally as much as a 30 percent market share of some games in the $1.2 billion electronic arcade game market. The imposters openly advertised their phony Pac-Man games in electronic video game magazines and sold them at international trade shows.

Some of the copies of its games were so accurate that they included the Midway company trademark insignia. The company said one of the few ways it could tell its games from the fakes was by the quality of the "joy handle" used to maneuver Pac-Man. Other copies went by the names "Puckman," "Packman," "Gobbler," "Puc-Man," and "Pac-Pac."

The ITC ruled that, until the president acts, importers of any fake Pac-Man games must post bonds equalling 54 percent of the price they pay for assembled games and 300 percent of the price of components shipped here. At first the counterfeiters only shipped assembled games through U.S. ports, but later started shipping computer game boards to be assembled into cabinetry here.

Although Pac-Man is a game, the case isn't a laughing matter. "It's very serious business involving the jobs of many people and the unlawful conduct we wanted stopped," said Paul Plaia, an attorney for Midway.

In March the ITC issued a temporary order prohibiting the sale of the counterfeit games here and cited 18 known producers. However, nearly 40 other foreign manufacturers of alleged imitations were named in Midway's complaint and never responded. They change trading companies with which they do business or change their identities, Plaia has said.

Midway's parent company, Bally Manufacturing Corp., spent $3.2 million on Pac-Man research and development in 1980, and about half of Midway's 1,600 employes at one time worked on Pac-Man.

Many small companies in Japan and Taiwan, using cheap labor, can copy 2,000 to 5,000 popular games in a very short time, according to an ITC staff report. When the Japanese market becomes saturated, the excess is shipped to the United States. Already, the Japanese are tiring of Pac-Man, the ITC report said.