“If it had to leave the eurozone, it would probably find its competitiveness once again, and then Greece could get itself back on its feet afterwards,” he told state broadcaster SR.
“It is a difficult and complicated path,” he said. “But it is difficult to see another that could work.”
Borg was speaking on the sidelines of an International Monetary Fund meeting in Tokyo.
EU member Sweden itself refused to join the eurozone and has made its opposition clear to plans for a European banking union.
Borg last month described the European Commission proposal “totally unacceptable”.
One of his objections is that it would oblige states that have been stricter about observing fiscal rules to assume the cost of bailing out those that had not.
Greece, with the backing of most of its population, is fighting to stay inside the eurozone, despite a lack of competitiveness that is likely to see it endure a sixth year of recession in 2013, according to official forecasts.