* Opposition leader alleges threats and vote-buying
* PM's party dismisses complaints
* Ruling conservatives expected to win third term (Recasts with opposition denouncing vote as unfair)
By Kole Casule
SKOPJE, April 27 (Reuters) - Macedonia's opposition will not recognize the results of Sunday's parliamentary and presidential elections, the leader of the main opposition party said after the vote, widely expected to hand the ruling conservatives a third term.
"A few minutes after the polls closed, I'm here to say that SDSM and our opposition coalition will not recognize the election process, neither the presidential nor the parliamentary," Zoran Zaev, leader of the centre-left SDSM, told reporters.
He accused Prime Minister Nikola Gruevski and his conservative VMRO-DPMNE party of "abusing the entire state system", saying there were "threats and blackmails and massive buying of voters" and demanded a new election.
Gruevski, 43, has ruled the landlocked ex-Yugoslav republic of 2 million people since 2006 in coalition with his ethnic Albanian partners, the DUI party. Surveys and analysts have widely forecast Gruevski and DUI to win a third term.
His party immediately dismissed the allegations as the opposition's attempt to manipulate voters.
"These have been the most peaceful elections so far," said Antonio Milosovski, a senior VMRO-DPMNE official.
"Although there were attempts by the opposition to show these elections as inefficient, the people did not allow that, they did not allow to be taken in by the manipulative scenarios from the opposition," he said.
Monitors from the Organisation for Security and Cooperation in Europe (OECS) will present their findings on Monday.
Gruevski's VMRO-DPNE could score a double victory as the vote coincided with a presidential runoff in which its candidate, the incumbent Gjorge Ivanov, looked set to beat a Social Democrat rival and win the largely ceremonial post.
Opposition parties have often accused Gruevski of creeping authoritarianism and corruption, while foreign diplomats in Skopje say there are concerns about media freedom and political pressure on journalists.
Gruevski says any complaints of authoritarianism come from opposition parties that lack a concrete political programme to unseat him. He has dismissed as false the corruption charges and has threatened lawsuits against SDSM's Zaev.
It was not immediately clear what concrete steps the opposition would take once the results are officially confirmed. The SDSM said "it was keeping all options open and would decide in the next few days". Preliminary results are expected around midnight (2200 GMT).
Macedonia remains one of Europe's poorest countries with unemployment above 28 percent, but Gruevski's government has achieved solid economic growth, low public debt and a rise in foreign investment, unlike most neighbours in the Balkans.
"It looks like a lost cause for the opposition, Gruevski is too strong," Skopje cab driver Dimitar Janeski said on Sunday.
Diplomats have praised Gruevski for keeping in check tensions between Macedonia's Slav majority and its large ethnic Albanian minority, whose rebellion in 2001 to secure more political rights brought the country to the brink of civil war.
But during his eight years in office, Skopje's bid to join the European Union and NATO has been frozen because of a row with neighbouring EU member Greece over Macedonia's name, which Athens wants changed because it is also the name of a northern Greek province.
Macedonia became a formal candidate for EU membership in 2005 but has made no progress since as Greece has continued to block it. Years of U.N.-mediated talks have yielded no results.
The parliamentary election was called a year ahead of schedule, after the coalition partners failed to agree on a consensus candidate for president. (Additional reporting by Fatos Bytyci in Tetovo; Writing by Zoran Radosavljevic; Editing by Andrew Roche)