Greece's Alexis Tsipras to step down as leader of Syriza

Party suffered large electoral defeat to conservative rivals in recent election

Alexis Tsipras will step down as leader of Greece's left-wing Syriza opposition party. AFP

Alexis Tsipras on Thursday said he would step down as leader of Greece's left-wing Syriza opposition party after a crushing defeat at the polls.

His announcement came after voters handed his conservative rival, New Democracy leader Kyriakos Mitsotakis, an imposing election victory for the second time in five weeks on Sunday, while Syriza lost tens of thousands of voters.

The conservatives landed their widest winning margin in almost 50 years, with Mr Mitsotakis securing a second term as Greek Prime Minister.

"There are times when crucial decisions have to be taken," an emotional Mr Tsipras, a former premier, told the press in Athens after a meeting of Syriza's executive.

He said he would call "elections within Syriza for a new leader, in which I will not be a candidate".

"A chapter is closing and a new one must be opened for our party," he said, adding that Syriza "needs renewal and major reforms".

For many Greeks, Mr Tsipras was the prime minister who nearly crashed Greece out of the euro, and who reneged on a vow of abolishing austerity to sign the country on to more painful bailout terms.

Syriza received less than 18 per cent of the vote, more than 20 points behind New Democracy.

After Mr Mitsotakis's victory, Mr Tsipras, 48, acknowledged a "serious political defeat" and said he was leaving his fate to the judgment of Syriza members.

"I'm used to not taking decisions in the heat of the moment," he said on Thursday.

"I took the time to reflect for three days to make a cool-headed decision."