The head of Deutsche Bank, Germany's biggest lender, warned Saturday that Europe faced a "make or break" moment as he prepared to fly to Greece amid debt talks between Athens and private creditors.

Speaking at the Munich Security Conference, Josef Ackermann said he was "flying to Greece tonight," but he gave no other details about his trip during a panel discussion about the crisis and its implications for world security.

"I think we are in a make or break situation and Greece plays a very important role," he said later in the debate that included Italian Prime Minister Mario Monti and World Bank chief Robert Zoellick.

"If we find a solution in the next few days, I think we are on the right track," he said.

Ackermann is also chairman of the Institute of International Finance (IIF), which is conducting the negotiations with Greece on behalf of banks.

Greece was under pressure to strike a deal with private lenders to wipe out part of its debt, as Athens faces loan repayments of 14.4 billion euros ($19 billion) on March 20.

The deal is a precondition for Athens to receive a new bailout from European partners and the IMf worth 130 billion euros ($171 billion).

In Athens, Greek Finance Minister Evangelos Venizelos warned that negotiations with the eurozone and the IMF were "on a knife edge" and that a deal needed to be sealed by Sunday night.

Ackermann said the private investors had been "extremely generous" in the negotiations with Greece by offering "a loss of over 70 percent" on their bond portfolios.

"I can only ask other constituencies to do the same," he said, in reference to governments and EU institutions such as the European Central Bank that also hold billions of euros in Greek debt.

Ackermann said Monti has been doing a "fantastic thing" in trying to pull his country away from the eurozone crisis, while "good things" have also been done in Spain, Portugal and Ireland.

"I think we are getting out of the crisis and markets are recognising that. But we have to fix the Greek problem," the banker said.

"If we see Greece collapsing, I think we are opening a Pandora's box."