A so-called Group of Friends including Belgium, Finland, France, Germany, Italy, Luxembourg, Netherlands, Slovenia and Spain issued an appeal to overhaul voting on the EU's Common Foreign and Security Policy.

It aims to "improve effectiveness and speed of our foreign-policy decision-making" in light of "Russia's war of aggression against Ukraine and the growing international challenges the EU is facing".

Rather than unanimity, the group called for a system called qualified majority voting on key defence and diplomatic questions.

Previous attempts to change the system have proved divisive.

While EU countries and institutions agree the bloc is too often cumbersome and bureaucratic, especially in emergencies, smaller countries fear their needs would be trampled if they lost their vetoes.

They argue they could lose out if all decisions were made via qualified majority voting, currently used for most EU business but not for certain circumscribed areas including foreign and security policy.

Such voting requires 15 of the 27 countries being in agreement -- as long as they represent more than 65 percent of EU's population of 450 million.

It favours France and Germany, the EU's two most populous nations.

Should a simple majority of EU countries -- 14 out of 27 -- vote to launch a treaty-change process, negotiations could then begin.

But any resulting text would require all 27 EU countries' ratification or approval -- and some countries could hold a referendum, creating a further hurdle.

In 2005, French and Dutch voters rejected a treaty that would have brought in a formal EU constitution.

The Group of Friends said it aimed to coordinate with EU institutions and work closely with all member states, inviting other countries to join its reform drive.