Italy's fomer Prime Minister Matteo Renzi has won the Partito Democratico (PD) primary election, earning back his position as the party's leader. With around 70% votes in his favour (according to preliminary estimates), he raced to the finish line way ahead of his contenders Justice Minister Andrea Orlando and regional governor Michele Emiliano.

Over 2 million party supporters participated in the caucus with Orlando earning 19% and Emiliano sweeping up 9% of the vote.

"This is an extraordinary responsibility. Heartfelt thanks to the women and men who believe in Italy," he wrote on Instagram on Sunday, 30 April ahead of the results.

Renzi resigned as PM in December following widespread rejection of a national referendum on constitutional reform. He was replaced by his Foreign Minister Paolo Gentiloni.

"Yes, we want to change Europe, we say it with humility and responsibility. We are not against Europe, we want a Europe that is able to represent its citizens, otherwise the alternative is populism," the 42-year-old told party members in his victory speech. "We will now move forward together.

"This is not the second half of the same match, it's a new match, he added."This is the beginning of a completely new story."

His win propels him towards the May 2018 parliamentary elections but both the PD and their new leader have a long way to go if they aim to keep control. Recent polls suggest that the party has slipped behind the populist anti-euro 5-Star Movement and Renzi himself is seen as a divisive figure.

"The government's horizon is 2018. Starting tomorrow, we'll work with Premier Gentiloni. Gentiloni's government is our government," said Agriculture Minister Maurizio Martina.