Stress tests on European banks should not reveal any "catastrophes" but the reviews should be tough, the chairman of euro zone finance ministers, Jean-Claude Juncker, was quoted as saying.

"I am not expecting any big catastrophes," he told Austrian newspaper Kurier. "But there cannot be any glossing over, the tests are based on reality," he said in an interview published on Friday.

The results of the stress tests will be released on July 23 and cover 91 banks.

Juncker also warned against understating the severity of the economic crisis facing the euro zone.

"Those that act as if all problems have been solved are guilty of misleading the public," he said. "The truth is that nobody knows how we will come out of the downturn. We need to rediscover our growth potential."

Juncker said the single currency was strong and still attractive to its members. "The euro will survive its critics, it is not in danger," he said.

"No country wants to leave it. This would be linked to fundamental economic consequences. No one is seriously thinking about leaving this solidarity zone."