NBA Commissioner Larry O'Brien announced yesterday agreement has been reached with players union representatives on a new three-year collective bargaining arrangement.

The NBA Board of Governors also voted to expand to Dallas next season -- with a catch.

The bargaining agreement is subject to approval by the NBA player representatives who will meet Monday in Washington. Larry Fleisher, the players association counsel, and Paul Silas, a Seattle player who is head of the players executive committee, said they will recommend acceptance of the agreement announced yesterday at the Washington Hilton.

O'Brien said the new contract would resolve the dispute over cable television revenues; provide for increases in minimum salary, per diem expenses and playoff money; limit the extent of deferred compensation that may be included in contracts and, in the final year, raise the size of rosters from 11 men to 12 and prohibit no-trade clauses in contracts.

Both O'Brien and Fleisher declined to give details on the contract until Monday's players meeting. But both left no doubt as to how they felt.

"This s the product of prolonged good-faith bargaining," said O'Brien. "I am proud that there was never any rancor expressed by either side."

"I will certainly recommend acceptance," Fleisher said."This proposal is the product of hard negotiations, and we think it's a major step forward."

Under terms of the agreement, which will run through the 1981-82 season, the NBA will have the highest minimum salary of any sport. The current NBA minimum is $30,000.

The move to Dallas will be accomplished under different terms - specifically, a higher price tag on the down payment -- than originally recommended by the owner's expansion committee.

The Dallas group, headed by former Buffalo Brave owner Norm Sonju, will be given 30 days to accept the Board of Governor's offer.

O'Brien said that three basic changes were made in the expansion terms for Dallas.

The entry fee will still be $12 million, but Dallas will have to come up with a $6 million down payment instead of $3.5 million. They also will have only five years to pay the remaining $6 million, plus interest, instead of six years.

Each of the NBA's existing 22 teams will be able to freeze eight players on its current roster instead of the proposed seven for the expansion draft that will help stock the new team. The Dallas team will pick 11th in each round of this year's regular college draft.

Sonju, who left immediately for Dallas after the meeting, said he did not know what problems the new provisions might cause.

"It's different news, that's for sure," Sonju said, "and it could be good news. I don't know but because it is different news, it has to be approved by our partners."

Seventeen votes were needed to approve expansion and 18 teams voted in favor with three against and one abstaining. The league did not announce which teams opposed or abstained.

Several NBA governors, including Jerry Buss of Los Angeles, Harry Mangurian of Boston, Mike Burke of New York and Bill Wirtz of Chicago, were opposed to admitting Dallas because of the low down payment in the original proposal. They were among eight club executives who met Saturday night in Buss' hotel suite to discuss the issue.

"The $12 million is a joke," said Mangurian. "It's a fictitious price, and we all know it.

"It makes no economic sense to participate in expansion," said Buss, who analyzed the figures and said the original proposal would net each of the 22 existing NBA teams only $26,000 per year.

In another development, the owners said they decided to enter an agreement with the Continental Basketball Association for next season that will basically set up a minor league for the players and a training ground for new officials.

Also Richie Phillips, legal counsel for the National Association of Basketball Referees, the union of the NBA officials, said he has encouraged the owners and O'Brien to go back to three-man officiating crews for this year's playoffs.

Phillips said that the coaches voted in favor of the proposal yesterday and that the competition and rules committed is also for it. "Only the owners are against it," he said.

The NABR's contract with the NBA expires at the end of this season and Phillips said his group will not sign a new contract for next season unless the three-official system is adopted.

"It could be a strikeable issue for next season," Phillips said.

The NBA used three officials last season, but voted it out for this year because of the cost, the owners said.

Phillips said that if the third official were added just for the playoffs this season, it would cost each team less than $2,000.