European Union (EU) leaders have formally agreed to launch negotiations on details of a Digital Green Certificate with lawmakers in the European Parliament in order to have a system that would enable travel by summer, according to an official statement.

The certificates would allow "safe free movement" within the EU for those already vaccinated against the deadly virus, those who recovered from Covid-19, or those with negative test results, Xinhua news agency quoted the statement issued on Wednesday by the EU Council as saying.

Restrictions on travel have had a heavy impact on the travel industry for well over a year, crippling tourism industries, especially in countries that are usually dependent on tourism.

"Important step forward: it brings us closer to our goal of having the certificate in place by June, to enable Europeans to travel safely this summer," European Commission President Ursula von der Leyen tweeted on Wednesday.

"The certificate will be accepted across the EU and available for everyone. For now, we have to remain cautious but it's time to prepare."

"The current epidemiological situation remains of great concern, but when looking ahead, we need to have solutions that work across member states," said Antonio Costa, Mrime Minister of Portugal, which currently holds the Council's rotating presidency.

"The Digital Green Certificate comes in to facilitate safe and free movement. It is most important for our citizens, for our societies and for the recovery of our economies."

The Digital Green Certificate's legal framework consists of two proposals.

The first concerns EU citizens and members of their families and the second concerns third-country nationals legally staying or legally residing in the territory of a member state.