The New Democracy party (ND) of Prime Minister Kyriakos Mitsotakis has won a landslide victory over its main rival, the left-wing Syriza party of Alexis Tsipras in Greece's national elections on Sunday, according to official preliminary results.  

With most polling stations processed, the ND reportedly had a 21-point lead over Syriza, but still no absolute majority.  

Greek Prime Minister Mitsotakis hailed the outcome as a "political earthquake" and a strong mandate for the ND.

But even if the ND has won the most seats, the lack of an outright victory means Mitsotakis will either have to seek coalition partners or choose to head to a new election.

Given the deep divides between Greek political parties, negotiations would likely be thorny, making a second vote likely in late June or early July.

In face of the results and the "uncertain" negotiations, Mitsotakis has hinted that a new election will be required to produce a strong government.

A new vote would be held with a new electoral law giving bonus seats to the winning party, making it easier for it to form a government on its own.

While dozens of parties were contesting the election, the vote primarily pitted Mitsotakis and his center-right party against Syriza, whose leader is also a former prime minister.

Exit polls showed only six or seven parties, out of 36 taking part, were likely to meet the 3% threshold to gain seats in the 300-member parliament.

Tsipras, who was prime minister of Greece from 2015 to 2019, called Mitsotakis on Sunday night to congratulate him on his victory.

What was the focus of the campaign?

Recent opinion polls put Mitsotakis' ND party in the lead. However, February's rail disaster, which killed 57 people, saw him lose his double-digit advantage.

He has also been embroiled in a wiretapping scandal, which saw the secret service phone-tapping Nikos Androulakis, leader of the socialist opposition PASOK party.

Mitsotakis, 55, was, however, quick to point out his government's achievements in recent years, including cutting taxes on businesses and also individuals.

Speaking after he cast his ballot, he urged voters to choose the stability he says he represents.

"Today we are voting for our future, for more and better jobs, for a more efficient health care system, for a stronger country with an important role in Europe and protected borders," he said.

The 48-year-old Alexis Tsipras, the current firebrand leader of the left-wing Syriza party, waged a campaign focused heavily on the rail disaster and wiretapping scandal.

On Sunday, Tsipras said the election day was "a day of hope."

"The citizens have in their hands the possibility ... to change the course of the country, to leave behind a difficult four years of inequalities, injustice, profiteering, job insecurity, auctions, indignity for pensioners, the targeting of the youth," he said, describing the current administration as "arrogant."  

Greece has been hard hit by a cost-of-living crisis that was a central theme in political campaigns leading up to the vote, as parties tried to attract voters with promises of job creation and better wages.

Lowered voting age

More than 9.8 million Greeks were eligible to vote in Sunday's general election for 300 lawmakers in the unicameral parliament who serve a four-year term.

The voting age has been lowered to 17 for the first time, while Greek citizens living abroad were also allowed to vote in the country in which they reside.

Polls at 22,000 voting stations closed at 19:00 local time (1600 UTC).

Ahead of the election, five people were arrested on suspicion of attempted vote-buying, with incriminating materials found in one of the suspect's cars, Athens News Agency reported.

Police found some 200 ID cards, passports and a bag with 114 envelopes, each containing a card of a parliamentary candidate and five ballot papers with the name of the candidate already ticked.

tj,kb/sms (Reuters, dpa, AP)