Spain plans to pour billions more euros into its troubled savings banks and force them to be more open about their lending practices, people familiar with the matter said, an acknowledgment that previous efforts to fix the banks have fallen flat as the country seeks to ward off an international bailout.

In a first step, Spain is preparing to issue €3 billion ($4 billion) in debt in coming days, the people familiar with the matter said. Government officials are putting plans in place to eventually raise as much as €30 billion, according to these people, though some say the final tally will be less.

The hope is that a series of capital injections will quell investor jitters about the savings banks, known as cajas (literally, "boxes"), which have been a thorn in Spain's side as it seeks to convince investors that the country's finances are stable.

The fate of the cajas is inextricably tied to the fate of Spain and potentially to the euro itself. Fear that the savings banks can't raise funds on their own and will need a government bailout was one reason ratings agency Moody's put Spain's rating on review for a downgrade last month.

Another step the government is taking to boost investor confidence in the cajas is simplifying their complex structures, making them more like traditional banks. The cajas have long had confusing ownership and governance structures and disclosed far less financial information than other banks. Their boards consisted of local politicians, union members, clients and, in some cases, Catholic priests, many of whom were reluctant to relinquish their influence over lending decisions.