MADRID ¨C Spain¡¯s newest drive to fast-track legal status for at least half a million undocumented migrants has already burdened immigration offices and sparked anxiety among prospective applicants weeks before the process even begins, a dozen union officials, lawyers, and migrants said.

A lack of information and state funding for the process could derail the planned mass amnesty announced by the Spanish government last month, said two people involved in the drive, which is the latest installment of the relatively inclusive migration policy credited with driving Spain¡¯s economic boom in recent years.

The Spanish government has said the drive will run from early April through June but has provided few details on the application process or documentation required. The migration ministry said on its website in January that no additional budget or staffing had been earmarked for the expected surge in applications.

That has unsettled both the migrants aspiring to use the legalization window, and the front-line workers at immigration offices already overloaded with a months-old backlog.

¡°Our offices are completely jammed. If there are no more people, if there is no technological reinforcement, without more money, this is impossible,¡± said Cesar Perez, a union leader for Spain¡¯s immigration officers.

Perez said most of his colleagues were still working through legal status applications submitted in June 2025.

Spain¡¯s government published a preliminary document on the drive last month. An unpublished draft of the full decree, dated Feb. 18, said ¡°a specific, preferential and differentiated procedure¡± would be developed for the legalization window but did not provide details.

Spain¡¯s ministries of Inclusion, Interior and Territorial Policy declined to respond to detailed questions from Reuters. A spokesperson for the ministry responsible for migration said the final decree was still being developed.

As other European countries tighten their borders, Spain¡¯s Socialist government has continued to champion migration, which economists credit for most of the country¡¯s fast-paced economic growth over the last four years.

Previous governments, including those led by conservatives, have offered multiple mass amnesty drives in recent decades. The largest was in 2005, when 570,000 people who could show they had formal work contracts were granted legal status.

There is an incentive for regularization: Spain needs approximately 2.4 million more people paying into social security over the next decade to sustain its welfare state, according to official estimates.

But disputes with splinter parties have disintegrated the current government¡¯s majority in the lower house of parliament. The resulting deadlock has prevented lawmakers from passing a budget since 2023 ¡ª and curtailed the government¡¯s ability to execute its new migration vision.

A lack of additional state funds for the 2026 drive would mark a policy departure from previous mass legalizations. In 2005, 1,700...