European Parliament President Martin Schulz labelled "irresponsible" Greece's refusal to work with the so-called troika of international bailout inspectors charged with overseeing the country's painful fiscal reforms.
"If the Greek government does not in fact want to work any more with its creditors on the current basis, I find that irresponsible," he said in German daily Frankfurter Allgemeine Zeitung.
His comments come after Greece's leftist new Finance Minister Yanis Varoufakis said Friday he wanted direct access to Greece's trio of creditors, the International Monetary Fund (IMF), European Union (EU) and European Central Bank (ECB).
Varoufakis pledged the government would no longer work with their widely-hated fiscal audit staff, known as the "troika".
Schulz, the first EU leader received by new Greek Prime Minister Alex Tsipras, said renegotiating Greece's debt could only be done "through consensus and not by provocation."
"We can bring (Greece) to a compromise, but there are no guarantees," Schulz said. "The situation is fragile, but not desperate."
Tsipras's Syriza party, which swept to power in parliamentary elections Sunday, has promised to provide relief from the austerity measures that were imposed on Greece by its creditors.
The new government has pledged to rip up the terms of the EU-ECB-IMF rescue package that helped Greeks avoid financial meltdown in 2010.
Tsipras's government has already reached out to France and Italy in search of support for a new deal on its debt.
Despite a restructuring in 2012, Greece is still grappling with a debt pile of more than 315 billion euros ($355 billion), which represents around 175 percent of its gross domestic product (GDP), a record for the EU.
German Chancellor Angela Merkel on Saturday ruled out fresh debt relief for Greece, telling the Hamburger Abendblatt daily: "There has already been voluntary debt forgiveness by private creditors, banks have already slashed billions from Greece's debt."