Elisa Rey puts a wad of yen into a small, brown envelope at her home. Far away in Peru, her monthly remittances -- set aside from her job in an electronics factory south of Tokyo -- have already built a house that few could dream of in her poor suburb of Lima.

Rey is one of thousands of foreigners who have migrated to Japan in the last decade and turned this country into an unexpected source of remittances that is supplying more money to developing countries than Tokyo's hefty foreign aid budget.

"The surge has been spectacular" in remittances from Japan, said Armando Ouchida, executive director of Convenio Kyodai, a cooperative used by many of Japan's 52,000 Peruvian residents, the country's fifth-largest foreign worker community, to send money home.