A member of the Senate Armed Services Committee said Monday that ratification of a U.S.-Soviet medium-range missile treaty is possible during the superpower summit that begins in six days but that some senators still have unanswered questions about the pact.

Sen. William Cohen, R-Maine, interviewed on the CBS-TV "This Morning" program about the Intermediate-range Nuclear Forces (INF) treaty, requiring the destruction of all U.S. and Soviet missiles with a range of 300 to 3,400 miles, said:"There are still some issues that senators (Jesse) Helms (R-N.C.), (Malcolm) Wallop (R-Wyo.), (Steve) Symms (R-Idaho) and others wish to be debated, and those will take a good part of this week to conclude."

He added that he thinks action is "unlikely . . . before the president leaves for Moscow, but said, "I think it's still possible that the treaty could be ratified while he's there."

President Reagan and Soviet leader Mikhail S. Gorbachev begin five days of meetings Sunday. Reagan leaves for Moscow on Wednesday.

Cohen said failure to ratify the treaty would be a serious mistake.

"I think that the treaty is verifiable," he said. "It's in our interest to proceed, and to reject the treaty, I think, would jeopardize not only our relationship with our allies but undermine the president's ability to continue to serve as a spokesman for this country."

The Senate on Friday crushed a bid by the Republican right wing to tie the treaty to ending Soviet cheating on other arms control accords. All five sections of an amendment offered by Symms were overwhelmingly rejected and other attempts to change the treaty were rebuffed.

But Senate leaders indicated that ratification before the summit would be difficult. Senate Majority Leader Robert C. Byrd, D-W.Va., said he may keep the Senate working late into the night this week and may schedule a Saturday session.

Sen. Dale Bumpers, D-Ark., blamed the conservative GOP senators for the delay, saying they do not want to see a successful summit.

"The treaty is going to be approved by the Senate. It's just a question of whether we do it before or after the summit," Bumpers said on the CBS show. "I think people who are opposed to the treaty feel that if it is approved by the Senate before then, the summit will be successful and they don't want a successful summit."