Following a weekend of intense negotiations, Salvini and M5S leader Luigi Di Maio had been widely expected to announce a "government agreement" and a nominee for prime minister on Monday afternoon.
But speaking to the press after a meeting with President Sergio Mattarella, Salvini seemed to cast doubt on the feasibility of an accord, saying that the two parties had "different visions" on certain "key issues" such as infrastructure, immigration and Italy's relations with the European Union.
He insisted that his party wanted a "free hand" to deal with illegal immigration and reiterated his eurosceptic stance, demanding the right to renegotiate the EU's fiscal rules.
"If I go to the government, I want to do what I promised the Italians," he said, adding that his party was not afraid to return to the polls if discussions failed.
Earlier in the afternoon Di Maio had adopted a more optimistic tone, telling reporters he had asked Mattarella for "a few more days" to come to an agreement with the League.
"We are writing what will be the government programme for the next five years and it's very important for us to finalize it as best as possible, so we have asked the president for a few more days to definitively close the discussion," Di Maio said after meeting Mattarella, adding that the final deal would be put to an online vote for Five Star members.
League leader Matteo Salvini and M5S leader Luigi Di Maio. Photos: Tiziana Fabi, Alberto Pizzoli/AFP
Italy has been in political deadlock since an inconclusive March 4th election, which was dominated by concerns over a struggling economy, the refugee crisis and illegal immigration.
Five Star and the League have been negotiating a power-sharing deal since last Wednesday, when Salvini's right-wing coalition partner, former prime minister Silvio Berlusconi, gave the green light for the pair to form a government without his Forza Italia party.
According to reports, the parties have agreed on rolling back increases to the age of retirement, while Five Star is willing to follow the League's hardline anti-immigration policies. Salvini and Di Maio are also willing to make compromises over their flagship policies – the League's drastic drop in taxes and Five Star's universal basic income – which look tricky to reconcile in one of the eurozone's most indebted countries.
The media also suggested the pair had agreed step back from their political ambitions and nominate a neutral candidate for the premiership. Both leaders insisted Monday that no names within their future cabinet would be made public before they had been approved by Mattarella.
The M5S emerged as Italy's largest single party in parliament by far after winning nearly 33 percent of the vote in March. Salvini's League won 17 percent, but it was part of a right-wing alliance including Forza Italia that garnered 37 percent of the vote.
On Monday, Salvini claimed to be speaking on behalf on the 12 million people who voted for the right-wing coalition, despite entering into negotiations with M5S without his allies and Berlusconi saying his party would not back an M5S-League alliance in parliament.
Photo: Alberto Pizzoli/AFP