Arnau Cañellas and Margarita Hernández of the Tax Agency. | Jaume Morey

The Tax Agency has let it be known that declarations for 2018 will be subject to "exhaustive control" to ensure that there are statements regarding overseas bank accounts, holiday lets and crypto money.

The annual declaration campaign started on Monday. Margarita Hernández, overseeing it in the Balearics, explained at a presentation that some 60,000 taxpayers in the Balearics with overseas accounts have been notified that they have to declare all income generated and that the agency has information through the international exchange system for accounts. The number of countries supplying information has gone up from 51 to 120, and these include tax havens such as Andorra.

Another 21,000 taxpayers have been notified about income from holiday lets. This information has been assisted by the obligation placed on websites to disclose details about owners who are renting out. The notifications for this have trebled, but Hernández suggests that they are just the first phase. More will follow. "The aim is to eradicate tax fraud, be it for tourist or residential letting - legal or illegal."

New this year is an emphasis on crypto money. The agency has sent out 440 notifications in respect of bitcoin transactions.

The agency's delegate in the Balearics, Arnau Cañellas, said that within 48 hours of the campaign starting, it had received almost 20,000 statements, of which 17,000 were seeking a refund. More than 4,000 of these have already been approved. The agency anticipates there being 526,048 declarations in all. Around 315,000 will involve a refund. It expects to take in 528 million euros and return 235 million.