Eurozone heads of state and finance ministers now routinely issue statements or take decisions for the 17 countries using the euro, creating a de-facto two-speed Union in the Council.
Some eurozone states have proposed that the European Parliament adapt by allowing a smaller group of MEPs to hold votes on legislation, relating to eurozone countries only - thus so creating a 'eurozone parliament'.
But Hannes Swoboda, chair of the Socialists & Democrats in the European Parliament, dismissed the notion out of hand. "The idea of creating a eurozone parliament is absolute nonsense and would be counter-productive," he told EurActiv.
"The euro is our currency, there is no need for a parliament at currency level. We have the European Parliament and national parliaments to work on the issues at hand, which they are doing,” he added.
European Commission President José Manuel Barroso is expected to present a proposal for an economic and monetary union at the 18-19 October summit of EU leaders, along with European Council President Herman Van Rompuy, Eurogroup President Jean-Claude Juncker, and ECB President Mario Draghi.
A final report and roadmap is expected to be adopted by EU leaders at the 13 December summit.
The four leaders presented an initial report, Towards a Genuine Economic and Monetary Union, at the June EU summit, and were tasked with continuing their work. However, opposition in the European Parliament is strong.
“The establishment of a eurozone parliament would be more of a hindrance than a help," said MEP Rebecca Harms, co-president of the Greens/EFA.
"It would blur the institutional architecture of Europe and undermine the community method,” she told EurActiv, stressing that the assembly as a whole should be responsible for democratic oversight and legislation for the eurozone.
Harms argued that the present system works, as evidenced by the enhanced cooperation tool, which allows EU member states to determine their speed of policy implementation, while remaining subject to the democratic control and legislation of the whole European Parliament.
“Decisions on eurozone matters also have an impact on citizens in EU member states outside the eurozone so why should they be denied a voice, through the European Parliament, on these matters?" Harms said.
"Splitting the European Parliament in this way might constitute a backwards step, away from our common values of European democracy,” she said.
Inner and outer cores
On the other side of the debate, Andrew Duff, a Liberal Democrat MEP and president of the Union of European Federalists, cautioned that a time might come when fiscal decisions - laws on tax matters for example - would be taken at the eurozone level, requiring a separation of MEPs into 'inner' and 'outer' cores.
"It would be scandalous for a Brit MEP like me to vote taxes on people that I wasn't directly representing and who aren't able to overthrow me," Duff argued.
Heads of political groups would at some point reach that stage of refinement, he argued.
A European Parliament spokesperson said the conference of presidents discussed yesterday (6 September) the broader question of the plan's drafting, but did not mention the particular proposal for a eurozone parliament.
During the discussion, all presidents concurred that it would be unacceptable for plans on the EU's future to be drafted without the European Parliament's participation.