Senate Minority Leader Howard H. Baker (R-Tenn.) said yesterday he has serious doubts about confirming Paul Warnke as strategic arms negotiator, and Sen. John C. Stennis (D-Miss.) announced that his Armed Services Committee will hear testimony from Warnke.

However, supporters of Warnke's nomination to head the Arms Control and Disarmament Agency as well as negotiate with the Soviets said they believe the trend is running in their favor.

"It looks increasingly good to me," Sen. Alan Cranston (D-Calif.) said yesterday, Cranston has been counting votes for the pro-Warnke forces.

Asked if Warnke would be confirmed by a two-thirds vote, Cranston said: That's the objective and I think we've got a good crack at it."

The Senate must approve any strategic arms treaty by a two-thirds vote. Some senators believe it would augurwell for a future agreement with the Soviets if Warnke could negotiate after receiving the support of two-thirds of the Senate.

"I think he's been damaged by it. I have gave doubts that he can do the job. I think he's been injured," Baker said, referring to the tesmony of foreign Relations Committee hearings Tuesday and Wednesday.

Majority Leader Robert C. Byrd (D-W Va.), who said he is keeping an open mind on the nomination, said that a good many senators feel that Soviets.

Byrd i snot working for the nomination, but he's not workfing against it and that's a help," a pro-Warnke worker said.

Some senators have suggested that Warnke be confirmed only as director of the agency, on grounds that the two jobs are too much for one man. Warnke suporter say they can defeat this move. They point to arms control progress made when Gerard C. Smith held both posts.

"We've gto a battle on our hands, but we're going to get him through for both positions," an aide to Warnke Senate backer said.

At a closed meeting yesterday morning, at which no vote was taken, the Armed Service Committee decided to hear Warnke testify.

Stennis said Warnke has agreed to to appear and that it is likely no other witnesses will be called. His appearance is tentatively set for Feb. 22. The Senate Foreign relations Committee, which has sole authority to report the nomination to the floor, will vote the same day.

Warnke has overwhelming support in the Foreign Relations Committee.

In Armed Services, only John C. Culver (D-lowa) opposed the unusual step of calling Warnke, Stennis said. Several members of the committee, notably Henry M. Jackson (D-Wash.), Strom Thurmond (R.S.C.) and Sam Nunn (D-Ga.), have raised objections to Warnke.

"I believe it would be a dangerous precedent to call Mr. Warnke prior to his confirmation," Culver said in a letter to Stennis.

Culver was the only member of Armed Service who accepted an invitation to participater in the Foreign Relations hearings. "The issues were fully aired," siad Culver, who suports Warnke.

He called the decision to summon Warnke "a reciprocal poaching precedent" that could lead to unending hearings on controversial nominations.