National Basketball Association officials said yesterday that an investigation has begun into Friday night's fight in Boston between the Celtics' Larry Bird and the Philadelphia 76ers' Julius Erving.

The fight broke out shortly after official Jack Madden suffered a knee injury early in the third period. That left referee Dick Bavetta to officiate the game alone. Boston won, 130-119.

"When you have just one official working, the brutality out there is unbelievable," Bird's teammate, Cedric Maxwell, said. "Players will do what they think they can get away with because you know that for every two fouls you commit, none will be called."

After the two forwards collided, sending Bird to the floor, Bird swung at Erving and missed. Then the 76ers' Moses Malone grabbed Bird in a headlock and Erving jabbed away at him.

Both benches emptied. The only injury was to Boston assistant Chris Ford, who received a bloody nose.

An NBA spokesman said that Scotty Stirling, the league's vice president of operations, will have a decision on the matter of possible fines or suspensions early next week.

A one-game suspension without pay would cost Erving about $14,700 and Bird about $24,000.