West Germany's opposition leader Hans-Jochen Vogel met with President Reagan yesterday and said later that it would be very hard for any chancellor to approve the planned deployment of medium-range nuclear missiles there in the absence of progress in arms control without creating major divisions within the West German public.

Vogel said he had sought to impress these problems on Reagan during their talks. He added that he regards the U.S. bargaining position at the arms control negotiations in Geneva--Reagan's "zero option" plan to bar U.S. and Soviet medium-range missiles from the European theater--as "an initial position" that almost certainly will have to be modified if an accord is to be reached.

He also said that, while Reagan had not told him so specifically, he received the impression here that the United States has "made no final decisions" about the talks and that "bargaining flexibility is possible" in the U.S. position.

At a luncheon with staff members of The Washington Post, Vogel said he stressed to Reagan the growing fear in West Germany and Western Europe of a nuclear holocaust and emphasized the need for success at the talks in Geneva.

Vogel and aides stressed that the situation in West Germany could become extremely tense this spring when preparations begin for deployment of the missiles. There has been widespread speculation that the site preparation and movement of equipment for the deployment could spark violent opposition to the plans.

At the Post, Vogel said that if the elections scheduled for March result in his becoming chancellor, his position on the scheduled missile deployment will be determined by his party's assessment of how serious Washington and Moscow have been in their efforts to reach an agreement.

"I don't exclude that we will have to agree to deployment if the Soviets don't move at all and if the Americans negotiate sincerely and flexibly," he said. But, "our first option is an agreement that makes it unnecessary to deploy the missiles."

That was a reference to the two-track strategy adopted by the North Atlantic Treaty Organization calling for going ahead with plans to begin deployment this year, while seeking an agreement that would reduce substantially Moscow's arsenal of medium-range missiles in exchange for canceling the NATO deployment.

That approach was approved by chancellor Helmut Schmidt, who preceded Vogel as Social Democratic leader, but opposition to deployment--even in the party--has made the matter an increasingly emotional issue.

Schmidt stepped down and the present Christian Democratic government has continued to support the original two-track approach.

The Social Democrats, after picking Vogel to succeed Schmidt last month, said that this fall the party's executive board will reassess the status of the Geneva negotiations and, on the basis of how members read U.S. and Soviet intentions, decide at that time whether to support deployment.