The European Economic and Monetary Union faces an eventual break up and the euro "disorderly debt workouts" should the euro zone fail to resolve its "economic and competitiveness divergence," economist Nouriel Roubini has said.

The monetary union "never fully satisfied the conditions for an optimal currency area," Roubini, co-founder and chairman of Roubini Global Economics, wrote in an op-ed in the Financial Times.

"Instead its leaders hoped that their lack of monetary, fiscal and exchange rate policies would in turn see an acceleration of structural reforms. These, it was hoped, would see productivity and growth rates converge," he said.

The way to restore competitiveness and growth for members on the periphery, said Roubini, would be to abandon the euro, restore their national currencies, and "achieve a massive nominal and real depreciation." While some may doubt the prospect of countries abandoning the euro, such as scenario "may not be so far-fetched five years from now, especially if some of the periphery economies stagnate.

"The euro zone was glued together by the convergence of low real interest rates sustaining growth, the hope that reforms could maintain convergence; and the prospect of eventual fiscal and political union.

"But now convergence is gone, reform is stalled, while fiscal and political union is a distant dream."