* EU lawmakers want to break all-male hold on top ECB posts
* Women candidates suggested for ECB bank-supervisor role
* Otherwise no female ECB board member likely until 2018
By Georgina Prodhan and Claire Davenport
BRUSSELS, Sept 25 (Reuters) - European Union lawmakers intend to use their role in shaping the euro zone's new banking supervisory authority to give a woman at least one of the top jobs in the European Central Bank's currently all-male senior management.
Lawmakers in the European Parliament, along with the European Commission, have been pushing EU member states to appoint women to the ECB's six-member Executive Board since Austria's Gertrude Tumpel-Gugerell stepped down in 2010.
"We notice that the EU member states' nominations to some of the most important... EU institutions result in an appallingly monotonous line-up of nominees," members of the European Parliament said in a letter to EU governments.
Euro zone heads of government appoint the members of the ECB's Executive Board. The European Parliament has no power to veto an appointment, but does cross-examine the nominee at a public hearing and holds a debate in a full sitting.
The ECB Governing Council has 23 members, including the six-member Executive Board and the heads of the 17 euro zone member central banks, who are chosen at a national level.
Earlier this month, members of the European Parliament delayed indefinitely the appointment of Luxembourg's Yves Mersch to the Executive Board, putting off his cross-examination in protest at what they called systemic bias against women.
Now they are trying to lobby for more women at the ECB as the bank embarks on key changes which would create a host of new positions.
Commission proposals for a banking union, unveiled on Sept. 12, include giving the ECB supervisory power over all the euro zone's banks and banks in EU countries that agree to take part.
In the new structure, lawmakers say they want women to be considered for the supervisor's board. The legislators say they would also prefer appointments from outside, to help avoid conflicts of interest in ensuring that the bank can handle both monetary policy and financial supervision.
"I think it's not wrong that colleagues feel strongly about the issue of women," Sven Giegold, a German member of the Green party who is steering some of the European Parliament's work on the new banking supervisor, told Reuters.
"And that many more feel strongly about potential conflicts of interest."
Giegold said unless a woman was found instead of Mersch for the current vacancy, there would be no opening on the bank's board until May 31, 2018, when ECB Vice President Vitor Constancio is scheduled to step down.
Tumpel-Gugerell and Sirkka Hamalainen of Finland are the only two women to have occupied posts on the Executive Board since it convened in 1998.
The ECB was not immediately available to comment.
Had Spain nominated former finance minister Elena Salgado for the board, analysts say she would have been a shoo-in candidate instead of Mersch.
But the Spanish government decided to go with the ECB's top lawyer, Antonio Sainz de Vicuna, whose nomination did not succeed, opening the way for Mersch to be appointed.
As members of the European Parliament begin consultations with the Commission and EU member states on a banking union, some legislators are pushing for an either/or: Either appoint a woman instead of Mersch, or appoint a woman to be part of the supervisory authority that will oversee banks.
In order to push the process, some members of the European Parliament have compiled a series of lists of women they believe are qualified for senior ECB positions.
The lists, one of which Reuters has seen, include women who hold senior roles at national central banks, investment banks and high-profile posts at universities.
Parliamentary officials said none of the women had yet been approached.
One such list includes Sabine Lautenschlaeger, vice-president of Germany's Bundesbank and Sinikka Salo, who has worked for both the ECB and the Bank of Finland.
The European Parliament will have to make a strong case for any candidate because it has legislative power over only one part of the banking union package -- tweaking the powers of the existing European Banking Authority (EBA).
National governments could in theory ignore the European Parliament's wish to have a woman, but Giegold said legislators were prepared to use their co-decision authority over the EBA as a bargaining chip.
The new supervisory structure is far from decided, but the Commission's proposal is for the head and deputy head of the new supervisory body to be from the ECB Governing Council.
Women hold 17 percent of the top roles in the central banks of the 27-member European Union, Commission research shows. But their representation falls dramatically the higher up the hierarchy one moves and is non-existent at the very top level.
The European Parliament's gender push at the ECB comes just weeks before the European Commission is expected to consider a proposal that large companies be obliged to fill at least 40 percent of their board seats with women.
At least nine member states are firmly opposed to the idea and have written to the Commission setting out their objections. (Additional reporting by Sakari Suoninen; Editing by Rex Merrifield)