European Commission President Jean-Claude Juncker’s proposal to expand Eurozone by bringing more countries into it has triggered controversy, mainly in Germany, where Chancellor Angela Merkel is seeking re-election.

On Wednesday this week, Juncker called for non-euro zone countries to adopt the single currency Euro so that the EU could find new unity after Britain’s planned departure in 2019.

Representatives for Germany’s Merkel-led government opposed the idea, arguing that Juncker’s call meant the EC would be very lenient in assessing the readiness of prospective states like Bulgaria or Romania for the single currency.

Greece entered the Euro zone in 2001, but later it turned out that Greece wasn’t financially well-equipped and ready to be an efficient member due to its falsified deficit statistics. It triggered a huge debt crisis, requiring other Eurozone countries to bailout Greece three times.

Austria also opposed the idea, warning that any such move would cause a fresh economic crisis in the Euro zone.

Countries outside the euro zone include Britain, Denmark, Poland, Bulgaria, Croatia, Hungry, Czech Republic, Romania and Sweden. The first two have formally opted-out from joining.