Beppe Grillo, head of the anti-establishment Five Star Movement that has rocked Italian politics, said on Wednesday Italy was already essentially out of the euro but denied being anti-European.
In an interview with German business daily Handelsblatt, Grillo said: "Italy is de facto already out of the euro. The country is on its knees."
"The northern European countries are only holding onto us until their banks have reclaimed their investments in Italian sovereign bonds. Then they'll drop us like a hot potato," said Grillo in comments published in German.
Comedian Grillo has unnerved markets and foreign investors with his attacks on unpopular austerity measures carried out in Italy as a response to the European debt crisis, as well as his call for a referendum on euro membership.
He reiterated his vow to hold an online plebiscite on the issue of Italy's membership of the common currency but disagreed that he was an "anti-European."
"I have only said we need a plan B. We need to ask 'What has become of Europe? Why do we have no common information policy? Why do we have no common tax or immigration policy? Why is only Germany getting richer?'," he said.
Rival party leaders have been left attempting to form a coalition government following the February 24-25 election, which saw the centre-left scrape to victory but fail to gain the crucial majority in the upper house of parliament.
Grillo has refused to negotiate with the centre-left party led by Pier Luigi Bersani and neither will enter into talks with billionaire former premier Silvio Berlusconi's centre-right coalition, which came a close second.
"The old parties are finished. They should give back what they have stolen and leave. Berlusconi is physically at the end. No one will be talking about Bersani in 15 days. We are at the start of a new era but they don't see it," he said.