The effect of huge bank debt on state finances almost forced Ireland and Cyprus to leave the euro zone before they received bailouts. And is now a major concern for Spain, which has received banking bailout money from the euro zone, and Slovenia, which is scrambling to avoid asking for a bailout.

German officials had warned that adding the politically fraught business of bank supervision to the E.C.B.’s responsibility for monetary policy would risk the bank’s independence.

 At the Dublin meeting last month, Mr. Schäuble insisted that a treaty change, to keep those areas of responsibility distinct, would eventually be needed for the banking supervisor to work effectively. That threw up an unexpected and potentially formidable roadblock.

He also said a treaty change would be needed to create institutions to share the burden of restructuring and closing banks.

Many other countries resist trying to make any changes to the European Union’s treaties at a time when Britain is already seeking modifications that many other member states oppose. And Europe’s economic problems have made many citizens so disenchanted with the Union that they might very likely vote down any treaty changes.

German officials continue to argue that it is more important to get the banking union right than to adopt it quickly. But supporters of a swifter pace regarded Mr. Schäuble’s go-slow message as blocking one of the few paths they see out of Europe’s debt trap.

Mr. Dijsselbloem, speaking on Tuesday in Brussels at an economics conference, emphasized the need to establish a banking union to enable the restructuring of shaky banks, and the orderly shutdown of failing ones, because the coming bank stress tests — which officials have dubbed an asset quality review — could raise new questions about some of those lenders’ viability.

“The outcome of that asset quality review we don't know yet, but it might be worrying,” Mr. Dijsselbloem said. “It might be worrying for some banks in some countries — we don’t exactly know.”

He added: “What I do know is that when we do have an outcome that is worrying, we need to have the instruments to deal with the problems. Because just exposing problems in banks and not having an answer how to recapitalize banks and how to strengthen them, that would be very dangerous.”

The comments by Mr. Dijsselbloem and Mr. Schäuble come against the backdrop of a worsening economic picture in the euro area and the wider Union. The deteriorating economy in the European Union is expected to drive unemployment to new highs this year in countries including Spain and Portugal that already are feeling acute pain.

“Unfortunately, unemployment is forecast to stay at the unbearable level of 11 percent in the E.U. and 12 percent in the euro area this year,” Olli Rehn, the E.U. commissioner for economic and monetary affairs, told the same conference in Brussels on Tuesday. “We expect a gradual turnaround to begin only next year,” he said.

Next Monday, euro zone finance ministers are to gather in Brussels for a monthly meeting overseen by Mr. Dijsselbloem. He is expected to lead talks to make progress on a rule book for directly injecting funds from the European bailout fund into troubled banks.