ROME, Sept 3 (Reuters) - Members of the anti-establishment 5-Star Movement backed a proposed coalition with the centre-left Democratic Party (PD) on Tuesday, 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. (Reporting by Gavin Jones; Editing by Crispian Balmer)