- Official results showed Mitsotakis's New Democracy party leading with 39.6% over Alexis Tsipras' Syriza party, with 69% of the vote counted.
- The early results also suggested that the far-right Golden Dawn party would be short of the 3% minimum needed to enter parliament, a fall from 7% of the vote at the last election.
Prime Minister-elect Kyriakos Mitsotakis told CNBC there was a strong mandate for change in Greece with his party set for an outright majority at Sunday's elections.
Official results showed Mitsotakis's New Democracy party leading with 39.6% over Alexis Tsipras' Syriza party, with 69% of the vote counted. The early results also suggested that the far-right Golden Dawn party would be short of the 3% minimum needed to enter parliament, a fall from 7% of the vote at the last election.
"It's an important victory for Europe, not just for Greece. It looks like Golden Dawn has not made it passed the 3% threshold which is a great victory for Greek democracy," Mitsotakis told CNBC's Silvia Amaro.
"And I'm very proud that I took over a party that was at 28% in the last election and taken it to almost 40%. I've received an outright majority which many people thought was inconceivable a few years ago, but that means there is a real strong mandate for change in Greece, and this what I have promised to deliver and this is what I will do," he added.
The opposition conservatives were on track to return to power by a landslide, unseating incumbent leftists blamed for foisting a bailout on the country which critics say was unnecessary.
Back in 2015, Tsipras and his Syriza party won the election with a promise of confronting the EU and ending austerity in a country that, since 2010, had been at the mercy of international creditors.
Tsipras' first group of ministers and its confrontational tone did not go down well in Brussels. Tsipras ended up calling a snap election later that year, winning it, and presenting a fresh team and ultimately achieving a stable work relationship with the country's creditors. The country ended its third consecutive bailout program last August, under Tsipras' leadership and the country's finance minister Euclid Tsakalotos.
Speaking to CNBC on Sunday afternoon, the outgoing minister for foreign affairs Giorgos Katrougalos explained why Alexis Tsipras did not get re-elected.
"I think that in all sectors we (Syriza) have improved the situation that we've had in the past. But the people expected more from us - more and faster. So I don't think that something went wrong. Simply the expectations of the people were greater than what we would deliver to them," he said.
There were three main events that dented Tsipras' popularity. First, the fact that he got elected on anti-austerity platform and still implemented some controversial measures during the third bailout program; second Tsipras ended a longstanding dispute with North Macedonia over the country's name — but some Greek citizens were not supportive of it; and finally, several wildfires that struck Greece last summer, leading to more than one hundred deaths. There has been a lot of discontentment at how Tsipras dealt with the situation.
Mitsotakis told CNBC Sunday evening his agenda is to grow the economy, to create more jobs and to "make sure that the Greek people feel safe again."
"The new government will be announced tomorrow, so I ask you for a little bit of patience for the new minister of finance, who will be sworn in on Tuesday, our first cabinet meeting on Wednesday and work begins as of tomorrow morning," he said when asked about the possible make-up of his government.
He had previously told CNBC that he intends to bring down the corporate tax rate to 20% in the next two years; to double the country's growth rate; and to negotiate lower primary budget surplus targets with Greece's creditors.
—Reuters and CNBC's Silvia Amaro contributed to this article.