Euro zone finance ministers told Greece on Saturday it could not go ahead with an agreed deal to restructure privately held debt until it guaranteed it would implement reforms needed to secure a second financing package from the euro zone and the IMF.

"We are moving relatively well on the application of the private sector portion, which is on a voluntary basis," Francois Baroin said on Europe 1 radio. "We hope not to go too far from the level that would move the Greek debt at around 120 percent. These are difficult discussions."

Greek Prime Minister Lucas Papademos said on Saturday he wanted to convince international lenders and political party leaders on Sunday to agree to the stringent terms of a 130 billion euro ($171 billion) rescue plan to stave off looming default.

Greece aims to submit a final debt swap offer to its private sector bondholders by February 13, a date Baroin said was the latest to conclude a deal.

Euro zone ministers are also dissatisfied with Greek Finance Minister Evangelos Venizelos, as they suspect him of paying more attention to his position within his party ahead of April elections, than to the reform talks.

"The Greek government has responsibilities and knows it," Baroin said. "The question is not about the Greek government's calendar, but the parliamentary calendar to put in place the reforms."

(Reporting By John Irish)

• A Permanent Economic Emergency