Beppe Grillo, whose anti-establishment party unexpectedly captured a quarter of the vote in Italy's inconclusive elections, wants to renegotiate his crisis-hit country's debt, according to a German report on Saturday.
"We are being crushed -- not by the euro but by our debt," the comedian-turned-populist firebrand told German weekly Focus.
"When (public debt) interest payments reach 100 billion euros ($1.3 billion) a year, we're dead. There are no alternatives" to debt renegotiation, Grillo was quoted as saying.
Grillo predicted his country's political system had "only six months" left before it collapsed and the state could no longer "pay pensions and public sector salaries".
If the debt obligations didn't change, the 64-year-old leader of the Five Star Movement said he would want his recession-struck country to leave the euro and return to the lira, the magazine said.
Drawing a comparison with the private market, Grillo added: "If I've bought shares in a company that goes bankrupt, then that's my bad luck. I took a risk, and lost."
With Italy scrambling to find a way out of the political impasse, Grillo could become kingmaker after his rogue party drew many austerity-weary Italians to its ranks.
But the party has spooked Europe with its promise to hold a referendum on the euro and cancel Italy's debts, prompting European leaders to urge Italy to stick to its fiscal commitments and form a government as soon as possible.
After meeting with Italian President Giorgio Napolitano on Friday, German Chancellor Angela Merkel expressed confidence in Italian politicians' "sense of responsibility", her spokesman said.
Also on Friday, Klaus-Peter Willsch, a deputy from Merkel's Christian Democratic Union (CDU), called for Italy to leave the euro if it could not stick to EU rules.
In the same edition of Focus magazine, Germany's Economy Minister and Vice Chancellor Philipp Roesler urged Italians to stay the course laid out by the outgoing government led by Mario Monti.
"Italy, as a major European economy, has a great responsibility. There is no alternative to the policy of structural reforms... I'm confident that those responsible in Italy recognise the importance of (preserving) stability," he was quoted as saying.
Official figures this week showed Italy's economy shrank by 2.4 percent last year and public debt rose to 127 percent of gross domestic product (GDP) from 120.8 percent in 2011 -- the highest level in the eurozone after Greece.