National Basketball Association commissioner Larry O'Brien said yesterday he is increasingly concerned about the possible spread of fighting among players and the potential for those fights to spark brawls among spectators in the stands and even with players on the court.

"This is extremely troublesome, extremely serious, O'Brien said. "It could escalate beyond fights among players such as the one between Kermit Washington and Rudy Tomjanovich. It could go to people beyond the players getting hurt and involved. We could have a situation in the arenas that would be horrendous."

O'Brien said the possibility of an escalating fight is one several items under study by a special NBA committee on violence he established several weeks ago.

Formed with the cooperation of the NBA Players Association and including representatives of coaches and general managers, the committee is to "review rules, producers and conduct of the game to determine what the root causes of this (violent) nature might ultimately be," O'Brien said.

NBA Players Association counsel Larry Fleisher, a member of the committee, said the players are equally concerned about violence getting out of control.

"At every one of our meetings of player representatives, the subject is brought up - mainly because the players don't want to see themselves as gladiators before screaming fans." Fleisher said. "The concept of being 'on show' is very disturbing to them. We're also concerned about the whole reaction of fans."

The committee's first meeting was Dec. 5, only five days before Los Angeles Laker forward Washington slugged Houston Rocket forward Tomjanovich.

Tomjanovich is to undergo surgery Saturday to repair facial, upper jaw and nose fractures. Physicians said his jaw will have to be wired shut for about six weeks and he may miss the rest of the season.

The doctors said the skull fracture he suffered actually was a dislodging of the bony structures of the face from the skull, causing spinal fluid to leak through the nose.

O'Brien suspended Washington for 60 days without pay and fined him an additional $10,000. The fine and loss of pay will cost Washington at least $53,560 in all. O'Brien said Washington could apply for readmission to the NBA after 60 days, but refused yesterday to say if his readmission would be tied to Tomjanovich's condition.

Earlier in the season, Laker center Kareem Abdul-Jabbar was fined $5,000 for retaliating with a blow against Milwaukee's Kent Benson.

Washington's penalty, the most stringent in NBA history, marks the first time the maximum fine of $10,000 has been meeted out since O'Brien asked the NBA board of governors to expand his disciplinary powers. Until last spring, the most punishment O'Brien could have imposed was a $500 fine and a five-day suspension. He now can suspend a player indefinitely and fine him $10,000.

O'Brien's get tough policy reflects a growing concern in professional sports about spread of violence. In a preseason memo to all clubs, National Football League commissioner Pete Rozelle deplored "unecessary violence" and threatened suspensions regardless of whether the player had been penalized in the game.

In baseball, the two league presidents can suspend indefinitely, but fines of more than $500 are subjects to arbitration. In hockey, fines and suspensions are at the discretion of executive vice president Brian O'Neill.

O'Brien said he asked for an expansion of his displinary powers because "the situation had reached the point where it was clear to me the authority I had . . . did not make the impact I wanted."

"There had been a dozen or more incidents (last season) when punches were thrown, but none brought the aftermath of these two." O'Brien said. "Those two incidents have taken on serious proportions beyond anything of recent vintage in the NBA."

The incidents were only two in almost 300 NBA games played so far this season, O'Brien noted, "But it doesn't afford me any comfort to point to only two serious incidents and say that, statisticall, the number is lower than at this point last year.

"My view is that if you have a dozen incidents of a serious nature, that's a dozen too many."

One of the issues the committee on violence is probing is the use of a third official. The NBAPA "overwhelmingly supports" the concept. O'Brien favors it, but cautions it will not be a panacea for ending violence or complaints about bad officiating.

There are different opinions about how a third official, should be used and the proposal has twice failed to get the necessary two-thirds vote of the board of governors.

One strong objection a third official is the estimated annual cost of $750,000 to $1 million. Fleisher says the cost is worth it if it results in better officiating.

The elimination or reduction of hand-checking also is being reviewed.

Both O'Brien and Fleisher discounted racial animosities as having any part in the recent brawls. Both the Washington and Abdul-Jabbar incidents involved black players striking white atheletes.

O'Brien also decried the labeling of some players as "enforcers" or "trouble-makers," remarking that the "evidence is decidedly lacking" to support the idea that some players actually fill those roles.