Greece's new left-wing government has begun a charm offensive across Europe in an effort to drum up support for a new debt deal -- but failed to convince the U.K. that it poses no threat to the euro zone economy.

Greece's Finance Minister, Yanis Varoufakis, met with U.K. Treasury chief George Osborne Monday to outline how the country will renegotiate its debt burden. However Osborne left the meeting with a stark warning for the euro zone.

Osborne said that the debt dispute between the new Greek government and the euro zone was fast becoming the biggest risk to the global economy.

"We had a constructive discussion, and it is clear that the stand-off between Greece and the euro zone is the greatest risk to the global economy," Osborne told reporters after the meeting, according to Reuters.

"I urge the Greek finance minister to act responsibly but it's also important that the euro zone has a better plan for jobs and growth," Osborne said.

After meeting the U.K. Chancellor, Varoufakis is scheduled address investors and banks in London.

The finance minister's tour of Europe started Sunday when he visited France to meet the country's Finance Minister Michel Sapin.

In a press conference following the meeting, Varoufakis said Athens had to wean itself off debt and did not want to accept more loans; Greece had resembled a drug addict in recent years, he said, waiting for another dose of aid.

For his part, Sapin said that while Greece's debt to gross domestic product (GDP) ratio of 175 percent was "untenable," there was "no question of France cancelling Greece's debt."

Varoufakis will then travel to Rome on Tuesday to talk with Italian Finance Minister Pier Carlo Padoan.