Constantine Mitsotakis, the conservative challenger, today predicted victory in Sunday's Greek election, but warned of a "slow slide toward totalitarianism," foreign policy "uncertainties" and economic disaster if Socialist Prime Minister Andreas Papandreou won a second term.

The relaxed 67-year-old leader of the New Democracy Party said, "We gained ground and are confident of victory." But previously optimistic aides hinted for the first time that crucial undecided voters were turning away from the party.

Noting that "only 6 percent of voters remained undecided" -- instead of the usual 15 percent in a final preelection week -- campaign manager Stefanos Manos said, "We've done our best, but we've not been able to force the debate on the real issues -- especially Greece's growing economic problems." He complained that the three-week campaign was "too short."

At several points in the interview, Mitsotakis seemed to be hinting that he was likely to lose the elections.

"We tried to be precise, realistic and sincere and did not hide the problems," he said of his issues-oriented campaign. "And we opened perspective for the Greek people to hope for a better future."

He said he believed "the Greek people will give a clear majority to the party it prefers" and avoid an "ambiguous situation" in which neither Socialists nor conservatives won a majority of the 300 seats in parliament. Such a situation would make the Communists arbiters of any future government.

Yet the candidate said that although he had preferred the absolute parliamentary majority won by Papandreou's Pan-Hellenic Socialist Movement (known as Pasok) in 1981, today, after such "negative results I prefer that Pasok not win" outright.

The alternative, a Communist-supported Pasok government, would be dissolved in favor of new elections "in a short time," he predicted. Moreover, he doubted that Papandreou "would take such a decision to cooperate with the Communists easily," because "the reaction inside Greece and abroad would be very strong."

Charging that with Papandreou "you cannot be sure of anything," Mitsotakis spoke of the increasing public "uncertainty and uneasiness" since the prime minister's controversial decision in March to withdraw support for outgoing president Constantine Karamanlis' reelection and to propose constitutional amendments restricting presidential powers.

On foreign policy, Mitsotakis reiterated his desire to "normalize" often strained relations with the United States -- "allies for whose aid we have reason to be thankful in the past" -- and the North Atlantic Treaty Organization.

Denouncing Papandreou's "bad theater" in foreign policy, Mitsotakis said "we must behave as real partners" inside the European Community. He said he favored a dialogue with Turkey, cast by Papandreou as the main threat to Greece.

Charging that Papandreou "had not said one word about foreign policy in the campaign," he denounced the silence as "strange, unacceptable and dangerous."

Turning to the threats to democratic institutions that he said would be posed by a second Pasok term, he warned of a "slow slide toward totalitarianism" that "even the Communists have begun to understand and criticize."