BRUSSELS—Euro-zone finance ministers meeting in Luxembourg Monday are on track to sign off on the final details of €440 billion ($527 billion) in loans intended to be a backstop if the Continent's sovereign-debt troubles deepen, European officials said.

The package is the largest piece of a €750 billion bailout assembled by European Union countries and the International Monetary Fund.

If a euro-zone country had trouble paying its debts, it could apply for the funding. Officials said a special purpose vehicle, set up to borrow money from capital markets and then dole it out to troubled nations, could be up and running this month.

Euro-zone leaders have already agreed on the basic structure of the package: A private vehicle chartered under Luxembourg law and owned by the 16 euro-zone countries would raise money with the guarantee of euro-zone members, then lend it out at a higher rate to the troubled country.

The structure is a bid to steer clear of EU prohibitions on direct purchases of member-state debt—a cornerstone meant to keep countries from being responsible for one another's affairs. The effort hasn't been without critics, especially in fiscally sound Germany, but the mechanism passed perhaps its highest hurdle last month when the German parliament gave approval for Germany's share of the credit guarantee.