MADRID — Spain appears poised to seek a bailout of its ailing banks, a long-anticipated acknowledgment by the government of Prime Minister Mariano Rajoy of the depths of Spain’s economic crisis.

The only questions might be when, and how much.

By some estimates, Spain’s banks might need as much as 100 billion euros ($125 billion). European leaders are said to prefer throwing a lifeline to Spanish banks now, though, rather than waiting for the banking problems to swamp Spain’s entire economy, which might require a full-scale bailout of the Spanish government that Europe can ill afford.

But the bailout cannot begin until Spain formally requests it. And while some European leaders press Madrid to get on with the process, the Spanish government says it wants a fuller accounting of how much money it actually needs. Officials from around the euro zone on Friday were deflecting news reports that finance ministers would be conferring over the weekend to draw up a rescue package.

On Friday, Spain’s deputy prime minister, Soraya Sáenz de Santamaría, suggested that her country would make no bailout request at least until after a banking audit expected Monday from the International Monetary Fund, as well as audits due June 21 from two independent consulting firms.