EU Economic Affairs Commissioner Pierre Moscovici on Thursday urged the bloc to wrap up its reforms of the eurozone this year before the European Parliament elections in May 2019 which could result in the rise in euro-sceptic and nationalist parties.
"We must absolutely concentrate our efforts on reforming the eurozone. We need to conclude in December," he told a conference in Madrid on the eve of a meeting of finance ministers from the 19 countries that share the euro to discuss economic reforms in the single currency area.
The upcoming European elections "will see a drop in support for traditional parties" that will result in a "more fragmented" European Parliament, he said.
And that could make reaching agreement on key eurozone reforms more difficult, Moscovici said following talks with Spanish Prime Minister Pedro Sanchez.
The reforms under discussion aim to connect eurozone economies more closely, make them more resilient to future crises, and to make banks more secure.
They include setting up a eurozone insurance programme for bank deposits and creating a pool of money to help eurozone governments weather troubles not of their own making.
Among the proposals is transforming the European Stability Mechanism - a rescue fund used in the event of financial crises - so that it could be used in the event of the failure of a major bank, instead of just to help countries in difficulty.
Another more ambitious measure defended by French President Emmanuel Macron calls for the creation of a joint budget for the eurozone, but is opposed by the Netherlands, Finland and the three Baltic states.
Moscovici said he had more confidence in the ability of the parties currently represented in the European parliament to reach agreement on reforms.
Spanish Economy Minister Nadia Calvino said the eurozone needed to "take advantage" of the economic growth that the bloc was enjoying to carry out reforms.
In an interview published in top-selling Spanish daily El Pais earlier on Thursday, Moscovici, 60, said he was mulling presenting himself as the Socialist candidate for the presidency of the European Commission, the executive arm of the European Union. "I will decide when the time comes, in the coming weeks," the former French economy minister told the newspaper.