Leading West German politicians maneuvering to become the president of this country next May are finding their reputations being tarnished by sudden public reminders of their wartime membership in Hitler's Nazi Party.

The latest casualty is the current president of West Germany. Walter Scheel, whose spokesman confirmed press reports yesterday that he had been a member of the party between 1942 and the end of the war while serving in the Luftwaffe.

The day before, another newspaper reported, and it was confirmed, that the speaker of the West German Bundestag, or senate, Karl Carstens, had been a Nazi Party member beginning in 1940. Carstens is a major figure on the right wing of the conservative opposition Christian Democratic Party and is being touted as a leading candidate for the presidency.

A few months ago, Christian Democratic State Governor Hans Filbinger, who also was being suggested as a presidential candidate, was not only tarnished by news reports of his Nazi background but was eventually driven from office when his behavior as a military judge during the era was disclosed.

In all cases, West Germany's highly politicized press has played a role, with a liberal religious weekly newspaper first raising Carstens' past and the conservative papers then turning their attention to Scheel, more in self-defence than in reputation.

There were at one time, some 10,700,000 Democrat Party here, the vital junior party to the much larger Social Democratic Party with whom they form the ruling coalition government.

Scheel has been president since 1974 and the 59-year-old, gray-haired diplomat, who was foreign minister underr former chancellor Willy Brandt, has won great respect both in West Germany and internationally in the postwar years.

The current Bonn government is hoping that Scheel will seek office for another five-year term precisely because he is so popular.

While real political power in West Germany lies in he chancellor's office, now occupied by Social Democrat Helmut Schmidt, the presidency, though largely a ceremonial office, does play an important representational role explaining West German policy at home and aboard.

The president is selected by a group of legislators representing the states and both houses of the West German parliament. Since conservative parties now control the upper house and the government's majority in the lower house is slim, the conservatives are likely to control the next presidential selection.

Carstens, 63, says he has never made any secret of his party membership, that it had been known and that an allied demazification panel examined his records in 1948 and gave him a clean bill for health. Such tribunals were standard procedure for millions of ex-Nazi party members.

In Carstens case, the court ruled that as a 23-year-old law student he was pressured to join the party and had not played an active role according to a tribunal transcript printed in the conservative newspaper Die Welt, which came to the speaker's defense yesterday.

Carstens' supporters see the issue as an effort to discredit him.

Like Carstens, Scheel was also cleared by an allied denazification tribunal and made no secret of his membership at the beginning of his postwar careeral though West German politicians understandably, also did not talk much about it either.

Sources in Scheel's party, however, said privately yesterday that they were surprised by the disclosures.

The president's spokesman said Scheel could not recall whether he applied for membership or if it had been granted automatically by the party in his home town in Solingen where, like most others, he had been a member of the Hitler Youth.

Whether Scheel or Carstens will be hurt by the disclosures is impossible to say at this point. Much of the West German press yesterday ignored the disclosures about Scheel.