Spain's left-wing government approved Tuesday a plan to regularise around 500,000 undocumented migrants by decree, the country's latest break with harsher policies elsewhere in Europe.

Migration Minister Elma Saiz said the beneficiaries would be able to work "in any sector, in any part of the country", and extolled "the positive impact" of migration.

"We are talking about estimations, probably more or less the figures may be around half a million people," she told public broadcaster RTVE.

Saiz said at a news conference after Tuesday's cabinet meeting that "we are strengthening a migration model based on human rights, integration, coexistence, and compatible with economic growth and social cohesion".

The measure will affect those living in Spain for at least five months and who applied for international protection before December 31, 2025.

Applicants must have a clean criminal record. The regularisation will also apply to their children who already live in Spain.

The application period is expected to open in April and continue until the end of June.

The plan will be passed through a decree that will not need approval in parliament, where the Socialist-led coalition lacks a majority.

The conservative and far-right opposition lashed out at the government, saying the regularisation would encourage more illegal immigration.

Alberto Nunez Feijoo, head of the Popular Party, the main right-wing opposition group, wrote on X that the "ludicrous" plan would "overwhelm our public services".

"In Socialist Spain, illegality is rewarded," he said, vowing to change migration policy "from top to bottom" if he took power.

Spain is one of Europe's main gateways for irregular migrants fleeing poverty, conflict and persecution, with tens of thousands of mostly sub-Saharan African arrivals landing in the Canary Islands archipelago off northwestern Africa.

According to the latest figures published by the National Statistics Institute, more than seven million foreigners live in Spain out of a total population of 49.4 million people.(AFP)