A woman walks past an Alpha Bank ATM and a shopping window announcing sales in central Athens, July 21, 2015. Yiannis Kourtoglou | Reuters

Leaving the euro might help struggling Greece, according to Otmar Issing, the former European Central Bank (ECB) board member and chief economist who is known as one of the euro currency's architects.

"The euro is irreversible – but if it is irreversible for every country has become an open question," Issing told CNBC on Tuesday.



Issing raised eyebrows earlier this summer when he said that the euro's irreversibility was an "illusion," contradicting current ECB members who have insisted that there is no going back from the single currency. However, economists and politicians away from the ECB have questioned whether highly indebted Greece can remain in the euro zone and whether it might in fact do better economically outside the currency union. "For Greece, there are very good arguments that it would do well outside the euro area for some time to come, but it all depends on the Greek government's reactions" Issing told CNBC. Greece has just begun a third much-needed bailout, after months of negotiations, which looked like they might result in a disorderly exit from the single currency region.