Double the number of illegal migrants than expected may benefit from a Spanish government plan to grant them official status, according to a police report.

The analysis, prepared by the National Centre for Immigration and Borders (CNIF), part of the national police, estimates that between 750,000 and one million illegal migrants currently living in Spain would apply for legal status.

According to the report, a further 250,000 to 350,000 asylum seekers could also seek legal status, bringing the potential total to between one million and 1.35 million people, El Confidencial news website reported.

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That compares with a public estimate of about 500,000 beneficiaries cited by the Socialist prime minister, Pedro Sánchez.

The CNIF document, dated January 29, suggests that most applicants would succeed. It warns the measure could trigger broader migratory effects, citing what it calls an “international perception of Spain as more permissive with irregular immigration”.

Police experts forecast “secondary movements” of between 200,000 and 250,000 illegal migrants per year from other Schengen-area countries into Spain over the medium to long term. The report also anticipates a “shift of maritime migration routes” from the central and eastern Mediterranean toward Spain, potentially increasing sea arrivals by 6,000 to 12,000 annually.

The assessment notes that Spain has not reinstated internal Schengen border controls, unlike several member states, including Germany, Italy and Poland.

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The government plans to allow applications from foreigners who can prove residence in Spain before December 31, 2025, and have stayed in the country at least five months.

Spain has carried out multiple extraordinary programmes to grant legal status since the return of democracy in 1975. El Pais reported that nine such efforts between 1986 and 2005 granted status to more than one million people.

Recent economic analysis has underlined immigration’s role in Spain’s growth as birth rates decline. A Funcas study said foreign-born workers accounted for 4.2 percentage points of Spain’s 8.9 per cent GDP growth between 2022 and 2025, while the foreign-born working-age population increased by 1.9 million.