Madrid regional premier Esperanza Aguirre on Monday proposed creating a legal and tax "island" in the region to accommodate the plans of US gambling king Sheldon Adelson to build a huge casino complex.

Sheldon's EuroVegas project, of 12 resorts with 36,000 rooms, six casinos, nine theaters and three golf courses would entail an investment of up to 18.8 billion euros through to 2022 and the creation of 261,000 jobs. But Sheldon in turn wants the land for the complex free, a very generous tax holiday and for the smoking ban in Spain to be waived at the development.

Speaking after a meeting with the new mayor of Madrid, Ana Botella, Aguirre pledged to uphold all of the region's "principles and values" regarding the project.