The head of the OECD warned Monday that Europe needs to present a plan to involve private investors into the global effort to help Greece and give Athens time to deal with its problems.

"Time is critical, time is important to avoid a liquidity problem becoming a solvency problem. Time is of the essence also in order to allow for a recovery of everyone," Angel Gurria, head of the Organization for Economic Cooperation and Development, told reporters.

Later on Monday the euro zone’s 17 finance ministers will be discussing the scenario for the private investors to contribute to the second bailout for Greece.

"Creditors should themselves contribute by extending the maturities (on debt) at least in the beginning, just extending the maturities long-term, allowing time for the policies to happen and then to be able to know better how much is required."

He said Greece needed time to carry out steps such as improved tax collection and its privatization plans.

"Then in a few years time, if we have prolonged the time and given ourselves this space, this oxygen, we will be in a better position to determine whether some reduction in the nominal amount of the debt is necessary," he said.