Former U.N. secretary general Kurt Waldheim, seeking to become Austria's head of state despite charges that was involved in Nazi war crimes, narrowly failed to win a majority of the vote in today's presidential election. A runoff is scheduled for June 8.

The inconclusive results seemed likely to keep alive the international controversy over the nature of Waldheim's role in a German military unit that brutalized Yugoslav partisans and deported Greek Jews to the Auschwitz death camp during World War II.

Waldheim's conservative backers had urged voters to grant him a first-round triumph to avoid prolonging the country's most bitter postwar campaign, one marred by overt displays of anti-Semitism, agonizing reflection on the Nazi annexation of Austria and hostile exchanges between the major parties.

The Interior Ministry announced tonight that Waldheim received 49.6 percent of the votes, just short of the 50 percent needed for an outright victory. Socialist candidate Kurt Steyrer won 43.7 percent and will be Waldheim's sole opponent in the final round.

An environmentalist candidate, Freda Meissner-Blau, did surprisingly well, receiving 5.5 percent of the vote. Political commentators speculated that she was aided by a surge of support following the Soviet nuclear accident. Otto Scrinzi, a right-wing pan-German nationalist and former Nazi SS member, received 1.2 percent.

Waldheim thanked Austrian voters for "the gift of such an impressive result," but he also betrayed some disappointment at not winning outright.

In a television interview after the results were announced, he dismissed the notion that foreign criticism of his wartime record could cause problems for him in representing Austria, saying that "these interventions have only come from private organizations and not from governments." He has repeatedly denied that he took part in any atrocities or was aware of them at the time.

Waldheim, 67, who was beaten badly in the 1971 presidential race here before he went to the United Nations, has promised to upgrade the largely ceremonial post by exercising its broad political powers, such as a limited right to dissolve parliament, that were ignored by Austria's five postwar presidents.

Since 1945, all of Austria's heads of state have been members of the Socialist Party or had its backing. A Waldheim victory June 8 would end this tradition and enhance the prospects of the conservative People's Party, which endorsed his candidacy, to wrest power from the ruling Socialists in parliamentary elections that must be held by next April.

Chancellor Fred Sinowatz, a Socialist, has warned voters that Waldheim's election could pose serious risks for Austria's international stature. In turn, the leader of the conservatives, Alois Mock, has charged the Socialist leadership with guiding a "smear" campaign against Waldheim. Mock also has appealed to the Austrians' "patriotic duty" in voting for Waldheim as a rejection of "foreign meddling."

"In five weeks, we will make Kurt Waldheim our new head of state and show the world that we Austrians vote for whom we want," Mock said tonight.

Sinowatz, who foresees the possibility of his left-of-center government being undercut by a conservative head of state working with the opposition, has claimed that a political "cohabitation" crisis could emerge from the presidential election. The Socialists are advocating a Steyrer victory in the second round as the only way to avoid severe political difficulties.

Steyrer, 65, a prominent Austrian physician and dermatologist who served from 1981 to 1985 as minister of health and environment, contended tonight that Waldheim clearly benefited from the controversy over his wartime past. "There was no doubt that a backlash provided a positive effect for my opponent," Steyrer said.

Other Socialist Party members said Austrian voters were still outraged by the charges raised two months ago by the New York-based World Jewish Congress, which accused Waldheim of covering up his complicity in Nazi war atrocities.

Waldheim is favored to win the second round, but Steyrer said he would put up a strong fight. He noted that he started the campaign with only 27 percent support and declared that he expected to continue chipping away at Waldheim's advantage.

Besides a large sympathy vote generated by attacks from abroad on his war history, Waldheim also capitalized on his high-profile diplomatic career. He acquired considerable prestige here because of his frequent meetings with world leaders while serving at the United Nations, an organization that has major offices in the Austrian capital.

In contrast, Steyrer is scarcely known outside Austria. The Socialist Party has sought to depict his lack of flair as a sign of personal integrity and inner strength but Steyrer has failed to generate much enthusiasm as a personality who can attract voters.

Steyrer served with the German Air Force as a medic during World War II and was awarded the Iron Cross for saving the life of an injured soldier while the unit was under direct artillery fire on the Russian front. He studied medicine in the military and became a doctor in April 1945.

Steyrer's name has not been associated with any German unit linked to war crimes, but in 1945 he was arrested and held by American forces for nearly seven weeks on the suspicion of carrying out an illegal abortion.

He was released without trial and insisted throughout the campaign that he had never conducted an abortion during his medical career. But he apparently alienated many Austrians, a majority of whom are Roman Catholic, by saying that he left the church because of his belief that women should have the right to abortions.