Syed Kamall, the leading British Tory MEP in the European Parliament, said such a development would be “divisive and dangerous”.
"To create a separate committee that only euro-zone MEPs may belong to sets a dangerous precedent. It is a case of divide and rule,” he said.
His comments came in response to a letter sent by British Liberal MEP Sharon Bowles, the chairwoman of the Parliament’s economic and monetary affairs committee (ECON), who called for a special sub-group to convene on areas related to the euro single currency.
The Bowles plan is currently only a recommendation, but Kamall said he feared a new economic and monetary union subcommittee would be pushed forward in June when the Parliament's new committee structure would be developed after the EU elections.
British Conservative MEPs, who would be excluded from the sub-group, fear that important decisions could be taken behind their back.
“This would have major implications for the UK to regulate its financial services sector as it sees fit, given the big steps towards federalisation of bank supervision and regulation that have taken place in recent months,” the Conservatives said in a statement.
The idea of creating a eurozone Parliament is not new and was recently relaunched by Germany's finance minister Wolfgang Schäuble, who said countries using the euro should be able to cooperate more closely on matters relevant to the single currency.
Andrew Duff, a British Liberal MEP and president of the Union of European Federalists, backs the idea, saying the 18 countries sharing the euro currency will in future increasingly take decisions on matters such as taxation, from which Britain will want to opt out.
"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 told EurActiv in a September 2012 interview.
But the idea of a eurozone Parliament is controversial, not only among British conservatives. Hannes Swoboda, chair of the Parliament’s Socialists and Democrats group, dismissed the notion out of hand. "The idea of creating a eurozone parliament is absolute nonsense and would be counter-productive," Swoboda told EurActiv in September 2012, when the idea was first floated.
"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,” Swoboda added.
The Bowles letter, which EurActiv has seen, says the Parliamentary sub-group “could be entrusted with the scrutiny of the EMU”, including banking union matters and the oversight of the eurozone’s financial stability mechanisms.
The strictly legislative role, however, would be kept by the existing parliament committees, which would go some way in soothing British concerns.
For the UK Conservatives, this is no less than a ploy to side-line Britain: "If it is felt necessary to create a separate committee for euro-only MEPs, then why on earth are MEPs from landlocked Austria able to vote on European marine policy?,” Kamall said.
“This represents a major attempt to curtail the influence of UK MEPs."