Greece's Prime Minister Kyriakos Mitsotakis said Monday he was seeking a new vote as soon as on June 25 in order to obtain a ruling majority, a day after his party won national elections that failed to produce a single-party government.

The conservative New Democracy party of Mitsotakis trounced its rivals in Sunday's vote, with a 20-point lead over its nearest contender -- Syriza, led by leftist Alexis Tsipras.

Voters handed the conservatives their best result since 2007, crediting the party with bringing economic stability back to a nation once known as an EU laggard.

"Shock and awe", headlined left-wing daily Efsyn on Monday, summing up the feeling shared by both New Democracy and Syriza voters, while pro-government Proto Thema noted that the double-digit margin was the widest seen since 1974.

The "political earthquake" hailed by Mitsotakis sent the Athens stock market to its highest in almost a decade.

But the win fell five seats short of an outright majority, leaving Mitsotakis with the option of either seeking a coalition or calling a new vote.

The 55-year-old Harvard graduate on Monday declined power sharing, telling President Katerina Sakallaropoulou, who handed him the mandate to form a government, that it was not possible to form a coalition under the current parliamentary line-up.

Greece should head for new elections "as soon as possible," he said.

Following Mitsotakis' rejection, Greece will continue going through the motions required under the constitution -- with the president then handing similar mandates to Syriza and then third-placed socialist party Pasok-Kinal.

The bids are also doomed to failure, given Sunday's result.

Hours after the vote, Tsipras, too, had set the stage for a new vote, saying the next battle will be "critical and final".

A senior judge will eventually be named interim prime minister and call for new elections.

- Economic stability -

In power over the last four years, former McKinsey consultant Mitsotakis steered the country through the pandemic which devastated Greece's vital tourism industry.

On his watch, the erstwhile EU economic headache has enjoyed a post-Covid revival, booking growth of 5.9 percent in 2022.

With unemployment and inflation falling, and growth this year projected at twice that of the European Union average, Greece's outlook was a far cry from the throes of the crippling debt crisis a decade ago.

Mitsotakis' term however was blighted by a wiretapping scandal as well as a train crash that claimed 57 lives in February.

The government initially blamed the accident -- Greece's worst-ever rail disaster -- on human error, even though the country's notoriously poor rail network has suffered from years of under-investment.

Nevertheless, neither the accident nor the wiretapping scandal appeared to have dented support for his conservatives -- who scored a far bigger win than that predicted by opinion polls ahead of the vote.

Despite the massive protests that broke out in the aftermath of the rail crash, the transport minister at the time, Kostas Karamanlis, was reelected on Sunday.

- Turn the tide -

Under a new electoral law that comes into play in the next ballot, the winner can obtain a bonus of up to 50 seats. Based on Sunday's showing and that calculation, New Democracy is virtually assured of a victory.

The left will likely seek to turn the tide by campaigning on cost-of-living problems which occupy many voters' minds.

But the centre-left vote remains splintered between Syriza and the socialist party Pasok-Kinal led by 44-year-old Nikos Androulakis -- a stumbling block for either party in the face of a consolidated right.

Tsipras is unlikely to face an immediate challenge for his Syriza leadership role. But he faces a tight deadline to recalibrate his approach ahead of the next polls.

His former maverick finance minister Yanis Varoufakis fared worse. His anti-austerity MeRA25 party failed to cross the three-percent threshold to make it to parliament.