Spanish authorities have found a substantial amount of cash hidden in Ibiza mega club Amnesia, according to Diario De Ibiza.

Apparently the money, alongside a money counting machine, was only uncovered with the help of pick axes.

According to the 2011 Commercial Register, Amnesia "declared an income of 13.1 million and a profit of only 18,822 euros."

Four people including the club’s owner, Martin Ferrer, have been arrested and are being questioned by authorities about suspected tax avoidance.

Amnesia was raided on Monday morning after Cocoon, with authorities returning to the club on Tuesday to conduct further searches of the mega club that lasted 17 hours.

At the time of writing the club is still operating its usual scheduled line-up.