BRUSSELS — After months of delays that could come too late to help boost hopes for a better summer, the European Union is still deliberating going ahead with Greek Prime Minister Kyriakos Mitsotakis’ idea of so-called “Green Passports” showing travelers have been vaccinated against COVID-19 or disease-free.

Without indicating why the EU is still stalling as the summer approaches, the Austria Press Agency said only 12 other of the 27 member states have so far been willing to back the idea to lure tourists.

The proposal so far is still said to be in outline form although tourism is a critical revenue engine for many countries in the EU, which is notorious for vacillating over proposals in seeking complete consensus.

According to the report, Austrian Tourism Minister Elisabeth Kostinger said the countries in agreement have worked out most of the details and will forward them to the European Commission for an approval.

The idea is to have the passport notifications in effect by June, way too late for many international travelers who make plans months in advance, although Greece is hoping they will come in big numbers again.

Kostinger said that the idea would be to have a certificate confirming that travelers are “COVID free” by showing proof of vaccination or having recovered from the Coronavirus or showing a negative test.

But the report said that the information will be stored on a QR code linked to a national database rather than a shared system that could raise questions about data protection violations.

Apart from Greece and Austria, the scheme also includes Bulgaria, Croatia, Cyprus, Denmark, France, Germany, Italy, Malta, Portugal, Slovenia and Spain but the EU’s 14 other members aren’t taking part as of now.