Members of Italy's anti-establishment Five Star Movement voted by a large majority on Tuesday in favour of a coalition with the centre-left Democratic Party (PD), opening the way for a new government to take office in the coming days.

In an online ballot, 79.3% of 5-Star supporters voted in favour of joining forces with the PD, their long-time political foes, while 20.7% opposed the alliance, party leader Luigi Di Maio told reporters.

The vote means Prime Minister Giuseppe Conte can now complete work on the new administration and present President Sergio Mattarella with a list of suggested ministers. He will then have to win confidence votes in both houses of parliament.

"This government will be neither on the left or on the right," Di Maio also said, adding: "It will be a government that does the things that need doing."

Conte's new cabinet must be agreed by Matterella and be approved by both houses of parliament before it can start working.

Di Maio, who served as deputy prime minister, industry minister and labour minister in the previous ruling coalition with the far-right League Party, is expected to become foreign minister.

Three names are being circulated for the key post of economic minister — the country must present a draft budget to the European Commission before the end of the month.

They are: Dario Scannapieco, a former Treasury official currently vice president of the European Investment Bank; PD's Roberto Gualtieri, now head of the European parliament's economic affairs commission; and Salvatore Rossi, a former deputy governor at the Bank of Italy.

The new cabinet is expected to be unveiled later on Wednesday.

The two parties' joint 26-point policy programme pledged to introduce a minimum salary, avoid a VAT hike set for January and boost spending on education, research and welfare. It also called for a tax on multinationals and the creation of a public bank to help boost development in the poorer south.

Changes to the controversial anti-immigration laws brought in by League leader and former Interior Minister Matteo Salvini including a ban for charity search and rescue boats to enter the country's territorial waters, are also expected to be altered or softened.

PD leader Nicola Zingaretti praised the joint programme on Twitter, adding: "Now let's change Italy."

Salvini, whose party is now out of power after his gamble to pull the plug on its coalition with the 5-Star Movement backfired, blasted the new administration as a "government of horrors, losers and slackers."

He said the two parties are "united only by the glue of hatred towards the League" and warned: "I will be even more determined, we are preparing to take this beautiful country in hand."