Walter F. O'Malley, owner of the Los Angeles Dodgers, said today that he believes the baseball commissioner has broad, sweeping powers, but they do not include ordering a league to expand or place a club in the Nation's Capital.

O'Malley was the leadoff witness today in federal court where a suit brought by Oakland A's owner Charles O. Finley against commissioner Bowie Kuhn for vetoing Finley's attempted $3.5 million sale of three players last summer is being heard.

While O'Malley's testimony took up much of the 13th day of the trial, the defense also got an assist from John H. Johnson, administration officer of the major league headquarters, who reviewed incidents in which he said Finley implicity acknowledged Kuhn's broad powers when asking for personal help.

Under questioning by defense lawyer Irvin B. Nathan, O'Malley said the intent of the club owners was to give the commissioner all-encompassing powers and that he personally led a drive in 1964 to restore those powers to the office that had been bereft of them for the preceding 20 years.

He added that the owners did not want to limit the commissioner's authority and agreed not to challenge his decisions in court, "because we'd be in court all the time instead of playing ball."

He also told of rejecting an offer by Bob Carpenter of the Philadelphia Phillies for $650,000 and five minor leaguers for the three star Dodgers players - Roy Campanella, Duke Snider and Gil Hodges - when he needed the money in 1956.

"I told Mr. Carpenter I was flattered and intrigued by his offer, but no way could I make that deal. I'd be breaking up one of the best teams in baseball."

But under questioning by Neil Papiano, Finley's lawyer, O'Malley put some restrictions on his views of Kuhn's powers in saying he disagreed with some other owners that Kuhn could interfere in league matters.

"He can't tell you to expand, but he could prevent you from expanding if he felt it was not in the best interests of baseball," O'Malley said. "Washington is probably the case you're referring to."

"O'Malley also said he disagreed that Kuhn had the authority to block the American League from expanding to Toronto until Washington was accommodated. At the time, the National League had voted, 10-2, to expand into Washington and Toronto, but needed a unanimous vote.

Saying he believes the unanimous consent rule should be changed, O'Malley added that, in retrospect, if Kuhn had suspended the NL constitution as some had requested, "We would probably not have the trouble with the Sisk Committee that we have found." He was referring to Rep. B.F. Sisk (D-Calif.) who chairs a special committee probing baseball and other professional sports.

"We're still working on the Washington problem to find a solution, but at the moment, we don't have one," O'Malley said. When asked if he knew of any effort by Kuhn to move the Oakland franchise, O'Malley said, "He was trying to accommodate the Washington situation. We understood that Mr. Finley was giving some consideration to that potential."

At last month's baseball convention, there was a proposal that the A's switch from the AL to the NL and move to Washington, but it never materialized after Finley was angered that word had slipped out about the plan.

Outside the courtroom, O'Malley said, "Everybody's working on placing a team in Washington. It's more serious than everybody realizes. We recognize it is something that should be accomplished. And believe me no one's working harder on getting a team there than the commissioner and me."

Asked what he meant by serious, O'Malley said the Sisk Committee was "part of it" but that there was still some opposition to expansion, although he could not rule it out.

Under questioning by defense lawyer Paul S. Reichler, Johnson, baseball's rules expert, told of Finley's asking Kuhn to block the Atlanta Braves' dave Johnson from leaving the country to play in Japan and asking Kuhn to allow him to substitute a player in the 1973 World Series.

Peter K. Blakely, chief defense counsel, said the defense would rest on Wednesday after Kuhn's testimony, but Papiano said he expects to continue his cross-examination of Kuhn on Thursday.