NBA Commissioner Larry O'Brien yesterday ordered Bullet guard John Lucas, who Tuesday admitted that he has a problem with cocaine, to undergo an extensive drug rehabilitation program. O'Brien said the league would take no punitive action against Lucas, and would allow him to continue playing during his rehabilitation.

However, O'Brien warned Lucas that "any recurrence of his involvement with drugs would result in an immediate suspension from the NBA."

At the direction of O'Brien, Lucas has been placed under the care of Dr. Steven Duvall, head of the Life Extension Institute, a national health organization program sponsored by the NBA and the NBA Players Association. One of the Life Extension Institute's major functions is to provide confidential drug and alcohol counseling to NBA players.

"John Lucas assured me that he is not now involved with drugs, and Dr. Duvall, who met privately with Lucas to evaluate the situation confirmed to me that in his professional judgment, such is the case," said O'Brien, after meeting several hours with Lucas yesterday. "While under no circumstances do I condone this past actions, I do sympathize with his problem, one which is not unusual in today's society.

"Therefore, taking into account the unique circumstance of his voluntary public disclosures, I have decided not to take punitive action at this time. I have accepted his statement that he is not now using drugs and his commitment that he will not resume such usage. This assurance, combined with his participation in the rehabilitation program, leads me to conclude that a suspension would not be in the best interest of John Lucas or the NBA."

Lucas, who was accompanied to the league headquarters in New York by his attorney, David Falk, said he was "thankful for this chance to prove that I have beaten my problem and will do everything necessary to complete this rehabilitation program. I know that if I fail, the next step is suspension."

Bullet Coach Gene Shue said he felt the league took the proper action and said he hopes this is the end of the matter.

Also present at the meeting were Jack Joyce, director of security for the NBA, and the NBA's attorneys.

Lucas, in Tuesday's editions of The Washington Post, admitted he has been using cocaine for more than two years and said it was the reason he missed a number of games and practices when he was with Golden State last season and with the Bullets this year.

The Life Extension Institute is in Minneapolis and it is uncertain in what manner Lucas will be counseled.