"To be the chair of Eurogroup, one has to be a minister. Portugal thinks it should continue like that", Mr Centeno said in the Socialist headquarters in Lisbon in response to questions asked by people on Twitter and Facebook.

Speaking about the possibility that he may be the next Eurogroup chair, he said "being the next chair of Eurogroup or not does not occupy my time at the moment ".

At the Iberian summit in Vila Real in late May, the Portuguese prime minister, António Costa, said that if Mr Centeio was to chair Eurogroup he would still remain in his ministry, because the rules demand that its leader is a minister.