Mike Trainer, attorney for Sugar Ray Leonard, said yesterday he has authorized Bob Arum to promote a welterweight title defense against Roberto Duran of Panama in May or June, the site to be selected later.

Arum, president of Top Rank Inc. of New York City, said he had cabled an offer of $1 million to Duran, the former lightweight champion and No. 1 contender for Leonard's World Boxing Council championship.

Arum stipulated that Duran must accept the offer by Feb. 15. Leonard is scheduled to make his first title defense against Davey Green of London on March 31 in Las Vegas.

If Duran does not meet Arum's deadline, Leonard plans to give former WBC champion Wilfred Benitez a return bout or to fight Jose (Pipino) Cuevas, the World Boxing Association welterweight champion.

Trainer said he had tried for six weeks to deal directly with Duran in arranging a bout.

"We wanted to get negotiations off dead center," Trainer said.

"Our experience has been that we do not need a promoter to sell Ray's bouts to the television people. When we agreed as the challenger to take $1 million while Benitez paid $1.2 million to defend his title, we were told how valuable the championship was. Now we want to see."

Duran's response to the direct approach was to sign up Don King to promote the title defense.

"King's proposition was unacceptable to us and our proposition was unacceptable to him," said Trainer. "We then signed a contract for Arum to promote one bout -- against Duran -- if -- if Arum can arrange it. We want to keep Leonard a free agent. We will retain the right to negotiate the television contract and the arrangement for the site."

Trainer said WBC regulations provide that if the champion and the mandatory challenger cannot agree on terms, the bout is to be put out for bids by promoters, with the titleholder to receive 75 percent of the purse and the challenger 25 percent.

"If Duran does not accept Arum's offer, he must step aside for some other challenger," Trainer said. "We've made a very attractive offer to Arum, and it's very attractive to Sugar Ray.

"If the Duran bout cannot be made by Arum, as free agents we can make arrangements for a bout with Benitez ourselves, both for the telecast and a site."