The EU refuses to recognise the new Venezuela assembly that gives President Nicolas Maduro new powers and is "ready to gradually step up" action if the situation deteriorates, diplomatic chief Federica Mogherini said Wednesday.

"The European Union and its member states therefore cannot recognise the Constituent Assembly as they have concerns over its effective representativeness and legitimacy," Mogherini said in a statement after meeting diplomats from the 28 European Union countries to discuss the situation.