Following a meeting of all Greek political parties on Thursday, Costas Karamanlis said "positive points [of the UN plan reunification plan] outnumber the negatives".
Karamanlis's half-hearted comment reflects Greek Cypriot opposition to the referendums on both sides of the island that could allow a reunited Cyprus join the European Union on 1 May.
Turkey and, according to opinion polls, Turkish Cypriots support reunification.
Call for delay
However, rank-and-file members of the largest Greek Cypriot political part have endorsed the leadership's call for a postponement of voting.
Some 65% backed the recommendation to allow more time to turn around the large opinion poll majorities among Greek Cypriots against the plan, while 34.4% voted against.
According to the resolution passed by the membership, if the UN does not postpone the referendum then AKEL will vote against the plan, practically dooming a yes outcome at the polls.
Party leader Demetris Christofias told the conference: "Under the current negative climate, even if AKEL said yes, it could not reverse a no vote."
Despite its membership of the governing coalition, the party has sought to distance itself from centre-right President Tassos Papadopoulos, who called on Greek Cypriots to oppose the plan in an emotional address to the nation last week.
But it appears the tide of public opinion has made the party think twice about the consequences of urging approval and the leadership has demanded a few more months to present the plan in a better light and negotiate "assurances" that Turkey will stick to its end of the bargain.
"We don't see any benefit to a delay, we think it's time to decide"
Senior US official
The membership's endorsement of the leadership's recommendation came despite US rejection of the proposed postponement following a telephone call with Christofias late Tuesday.
"We don't see any benefit to a delay, we think it's time to decide," a senior US official said, after the AKEL leader discussed the idea with Secretary of State Colin Powell.
Carrot and stick aid
The United States on Thursday pledged $400 million for a re-united Cyprus if both Greek and Turkish communities back the UN peace.
Andrew Natsios, the administrator of the US Agency for International Development, told a pre-donors' conference on Cyprus in Brussels and promised the funds "given a positive outcome".
"We urge other donor governments and international organisations to make a similar commitment," he added.
The United Nations had already made clear that all parties would have to agree to any delay and Ankara had said a firm no.
Cyprus has been divided since 1974 when Turkey occupied its northern third in response to a Greek Cypriot coup aimed at uniting the island with Greece.