Denver oilman Marvin Davis said yesterday he and Charles O. Finley have ended their negotiations for the sale of the Oakland A's.

Davis offered to buy the American League team for a reported $12 million on Dec. 14. Officials of the Oakland Coliseum immediately filed suit to stop the sale because of the 10 years remaining on the lease Finley signed when he brought the A's there from Kansas City before the 1968 season.

The deal, Davis said then, was contingent on receiving the team "free and clear of any encumbrances." Last week, Davis gave Finley and Oakland officials until the weekend to resolve their differences or, Davis said, he would withdraw his offer.

Meetings reportedly continued yesterday in San Francisco between Oakland and San Francisco city and baseball officials. It had been suggested that the San Francisco Giants of the National League might be able to play some of their home games at the Coliseum.

Both teams have suffered from low attendance figures over the last few years, with Oakland drawing the smallest number of fans in both leagues at its home games.

"I'll have to stay in Oakland," Finley said in Chicago. "I haven't talked to Mr. Davis today, but he has been saying over the last couple of weeks that he couldn't wait any longer.

"Mr. Davis has been very considerate and extremely patient. I can't fault him at all. I can't fault anyone. Oakland people were very cooperative, but the San Francisco people have not been very cooperative."

Finley said that Oakland officials had told him that if the San Francisco Giants would play half their games in Oakland, they would be willing to work out an end to the lease.

Asked if he now would try to sell the club to Bay Area interests, Finley said, "No one wants to buy a club in Oakland. Why should they want to buy a license to lose?"

When notified of Davis' decision, Giant president Robert Lurie said, "We're just going ahead with our plans. I was hopeful that the A's would leave and we'd be playing some of the games in Oakland. But now we won't."

Under the terms of the 20-year agreement with the Coliseum, Finley agreed to pay a minimum of $125,000 a year in rent. There also is a clause in the agreement that the club could play nowhere else over the 20-year period.

Davis, who said in December he never followed baseball until he began considering the A's purchase, planned to have the team play at Mile High Stadium here. The American Association champion Denver Bears drew 195,000 fans last season, and the 55,000-seat stadium - which is expanded to seat 75,000 for football - was a consistent sellout for the National Football League Denver Broncos.