The leader of the 5-Star Movement has said he wants an online vote on Italy's membership of the euro, in an interview with a German magazine published on Sunday.
"I am a strong advocate of Europe. I am in favour of an online referendum on the euro," Beppe Grillo told Bild am Sonntag.
Such a vote would not be legally binding in Italy, where referendums can only be used to repeal laws or parts of laws, but would carry political weight. Grillo has said in the past that membership of the euro should be up to the Italian people.
The spectacular rise of the 5-Star Movement, which gained 26 percent of lower house votes in its first ever parliamentary election, rattled markets concerned that the political newcomers could turn against austerity and membership of the euro, and plunge the currency zone back into crisis.
The three leading groups to emerge from the vote have yet to agree on how to form a government. The centre-left group took a majority in the lower house but not in the Senate, meaning it must agree an alliance with either 5-Star or traditional rivals the centre right in order to govern.
Grillo - who did not run for a seat himself as he has a criminal conviction which excludes him under his own movement's rules - has repeatedly said his group will not enter a coalition, but would support individual bills in line with their programme.
The former comedian also said he was in favour of Italy repurchasing its government bonds and renegotiating the interest rate.
"In reality Italy has long been lost. In one year we won't have enough money left to pay the pensions and wages of those working in the public sector. There's not much left to rescue," he said in the interview.
In central Rome 5-Star activists symbolically entered the lower house of parliament on the day when it opens to the public once a month, "to get to know the place that will finally be once more familiar to its real owners, the Italian citizens", according to an online invitation to the event.
"The euro referendum is not the most important thing for the majority of 5-Star activists. The euro is not the problem. The problem is the way that European policy is made, ignoring the interests of citizens," said Armando, a 5-Star activist, as he queued with his two children to enter the 17th-century palace.
During the election campaign Grillo said his deputies would open parliament "like a tin of tuna" and bring greater transparency to the workings of government.
"A referendum on the euro is not a priority. What is important is that the movement brings about change to the country," said 5-Star activist Alessandro, a restaurant worker, 44, as a brass band played in the square.
Neither agreed to give their surnames. The newly-elected parliamentarians are set to meet for the first time early this week to discuss strategy, and movement members have been advised not to speak to media.
(Writing by Naomi O'Leary; additional reporting by Michelle Martin in Berlin; editing by Andrew Roche)