The Spanish government has been flooded with thousands of inquiries about legislation it approved last month that will grant dual citizenship to descendants of Sephardic Jews expelled from Spain more than 500 years ago, the country’s justice minister said on Wednesday.

The minister, Alberto Ruiz-Gallardón, who considers the legislation his most important achievement, said in an interview at The New York Times that he anticipated that more than 150,000 people, scattered in the Sephardic Jewish diaspora, would seek Spanish citizenship under the measure, aimed at righting what the government has called a grievous error. The bill is expected to receive unanimous parliamentary approval.

“This law is a real historic reparation of, I dare say, the biggest mistake in Spanish history,” Mr. Gallardón said. He was visiting New York at the invitation of Jewish groups to explain the legislation, which has generated intense interest.

Spain’s roughly 200,000 Jews were ordered expelled in 1492 by Queen Isabella and King Ferdinand, who gave them four months to leave. Many were forced to sell their homes and businesses for nearly nothing, with many eventually resettling in other areas of Europe and North Africa bordering the Mediterranean, but also migrating elsewhere.