By Francesco Guarascio
BRUSSELS (Reuters) - Center-left leaders could try to oust Donald Tusk as chair of the European Council and key broker of Brexit negotiations with Britain and will have their first discussion on the issue next week before an EU summit in Malta, their party president said.
Center-left lawmakers are fuming over the loss of the European Parliament's presidency to the main center-right grouping, which already heads the EU's other key institutions, the European Council and the executive European Commission.
The center-right's Antonio Tajani of Italy replaced German Social Democrat Martin Schulz as president of the Parliament in a vote last week. Luxembourg's Jean-Claude Juncker is president of the Commission.
"It is not logical that one political party that had less than one third of the votes in the European elections have three out of the three key positions," Sergei Stanishev, head of the European Socialists and Democrats (S&D) party, told Reuters in an interview late on Tuesday.
"I think a conversation about a progressive candidate for the presidency of the European Council should be initiated among our prime ministers and heads of state," Stanishev, a former Bulgarian premier, said.
He said he would propose the start of such a debate at a meeting of Socialist leaders due to take place next week in Malta, just before an EU summit on Feb. 3.
The European Council, which groups the 28 EU heads of state and government, must decide by May whether to give Tusk a second, 30-month mandate. They will prefer a consensus choice, though if need be can take a majority vote. Nine EU countries are currently led by the center-left.
Tusk, a center-right former Polish prime minister, has not said whether he wants a second term.
Arguing in Tusk's favor, diplomats say, is a broad view that he has done a fair job in a time of crisis and a preference for continuity, especially as he prepares to oversee complex negotiations on Britain's exit from the European Union.
The issue of party affiliation has rarely been a top priority for EU leaders when they decide such appointments.
Stanishev declined to comment on a report, denied by aides to Francois Hollande, that the French Socialist leader might like to replace Tusk after France's presidential election in May. Hollande is not seeking re-election.
"It is not about personality. It is a matter of political balance," said Stanishev, adding that the center-right's stranglehold on top EU posts could also help fuel the rise of euroskeptic, far-right parties across the continent.
(Editing by Alastair Macdonald and Gareth Jones)