Brussels: European Parliament lawmakers said on Friday that they could hold up plans for a euro zone banking union after EU member states ignored the parliament’s demands over gender balance on the European Central Bank’s (ECB) board.

The parliament last week voted against member states’ choice of Luxembourg central banker Yves Mersch for a vacant post on the ECB executive board, demanding greater efforts to find a female candidate for the job.

But the 27 member states on Wednesday launched the final formal step to appoint Mersch. Confirmation is now expected on Monday.

Sylvie Goulard, a French liberal member of the parliament’s economics committee, said the member states’ bulldozing of Mersch’s appointment could cause a delay in a banking union, which is designed to stabilise the euro zone financial system.

“Do you really think they will get a decision on time and with mutual trust if they go ahead like this?” she said.

The banking union was announced in September by the European Commission, the EU executive. The European Parliament and the EU states are aiming to complete the project by the end of the year.

The union is set to have three major steps: the ECB takes over monitoring euro zone banks and others that sign up; a single fund is created to close down and settle the debts of failed banks; and a comprehensive scheme to protect savers’ deposits is established.

In spite of their threats, the parliament has a limited say on the proposal. Its main power is an equal say with the member states over the role of the existing European Banking Authority under the new structure, a small but important element of the entire proposal.

The need for co-operation between member states and the parliament meant that it would be “a very big mistake” for the states to go ahead and appoint Mersch, said Sven Giegold, one of two lawmakers leading the body’s work on the union said.

“The solution to the euro crisis rests on the sincere co-operation of the institutions, for instance, on a banking union,” he said.

Giegold, a member of Germany’s Green Party, said the parliament could use their power over the EBA as a bargaining chip for other issues such as making sure that non-euro zone countries’ concerns are also heard under the new system.

Many lawmakers say the EBA, set up to coordinate the supervision of banks and run by regulators from across the European Union, could act as a counterbalance to the ECB once it receives new sweeping powers under the proposal.

Lawmakers said on Friday that they were still trying to stop the appointment of Mersch by lobbying governments to object at the last minute.

“Of course we are not sure to win,” Goulard said.

EU sources say that on Monday the European Council, which represents EU member states in Brussels, will receive a final confirmation by fax from EU member states for Mersch’s appointment.

It would take just one country to halt Mersch’s appointment on Monday. But a source close to the matter said this would be an “extraordinary” U-turn by heads of state who have already backed Mersch.

The source said he doubted that in the current climate a head of state would want to delay the completion of the ECB board.

Two EU sources said on Wednesday that Mersch’s appointment would go ahead.

The parliament’s rejection of Mersch has been criticised as an unwelcome stumbling block at a time of crisis.

Still, some analysts see lawmakers’ intervention as significant at a time when EU institutions are struggling to interest the European public.

Guntram Wolff of the Bruegel think tank said the parliament would do well to prioritise democracy and that he believes the banking union is not a panacea to the crisis.

“I think there is a misperception in the public and the financial markets that the banking union is the immediate solution to the crisis,” Wolff said.

Though the parliament has limited powers, Wolff said it should exploit its status as the only elected body in the EU. The next European Parliament elections start on June 5, 2014.

“They can, of course, try to influence public opinion and I think they have very powerful allies.”

Wolff said the parliament should tap common concerns it has over the banking union with the 10 non-euro zone countries, creating the possibility for an alliance.

Britain, home to Europe’s biggest financial centre and who is also outside the scheme, could be a powerful ally. It is pushing for changes to dilute the power of the European Central Bank.