Talks on forming a new Italian government risked being further delayed on Wednesday after the populist Five Star Movement (M5S) postponed a vote on whether to participate.

The M5S, the biggest party in parliament, is split over whether to support a national unity administration led by Mario Draghi, the former head of the European Central Bank brought in after the previous centre-left government collapsed.

M5S members were asked to have their say in an online vote due to take place over 24 hours on Wednesday and Thursday - but this has now been delayed indefinitely.

"The vote on the government... is temporarily suspended. The new start and end times for the vote will be announced later," acting M5S leader Vito Crimi announced Wednesday on the party's blog.

M5S had indicated it was open to joining Draghi but in a video posted late Tuesday, its founder Beppe Grillo urged members to wait a little longer before deciding.

"Let's wait for him to say publicly what he wants to do," Grillo said, referring to Draghi.

Italy has been devastated by the coronavirus pandemic that plunged the country into its worst recession since World War II and claimed more than 92,000 lives.

But it has been without a fully functioning government for almost a month since Giuseppe Conte's coalition collapsed.

President Sergio Mattarella called in Draghi last week, after Conte finally resigned, to try to build a new broad-based coalition.

Commentators had suggested Draghi could wrap up negotiations this week and announce a new cabinet by Friday.