A U.N. human rights expert is denouncing the conviction of two "whistleblowers" found guilty in Luxembourg for leaking secret documents to a journalist investigating sweetheart deals that saved billions of dollars in taxes for foreign companies including Apple, Pepsi and Ikea.

A statement from Alfred de Zayas says the two former PricewaterhouseCoopers employees revealed "how tax avoidance and tax evasion occurred in Luxembourg banks" in the so-called LuxLeaks scandal.

De Zayas called whistleblowers "heroes of our time" and said "we seem to live in an upside-down world in which whistleblowers are convicted and those who loot society are not."

Thursday's comments come a day after a local Luxembourg court convicted ex-PwC workers Antoine Deltour and Raphael Halet of stealing private documents and sentenced them to suspended prison terms.