Nobel Literature prize winner Mario Vargas Llosa on Monday expressed ambivalence towards whistleblower website WikiLeaks, hailing increased openness but cautioning that too much transparency could be dangerous.

"My opinion (about WikiLeaks) is contradictory," admitted the 2010 laureate, who is known for his opposition to totalitarian regimes, at a press conference in Stockholm.

"On one hand, I think the transparency is wonderful, that everything is brought out into the light. This protects us from intrigue, ploys and lies," the Peruvian author said, just days before he is to receive his Nobel Prize at a ceremony in the Swedish capital on Friday.

"On the other hand, if everything comes out into the light, if all forms of confidentiality, of privacy, disappear, I do not know how a state could function," he added.

"In simple terms, states would be placed in such a vulnerable position that institutions ..., the very essence of democracy, would be in danger," said Vargas Llosa, himself a former presidential candidate in Peru.

He said it was "paradoxical" that it was the most democratic states that were "the most vulnerable to this kind of exposure," while "dictatorships are saved" precisely because of the lack of openness in their regimes.

A former leftist who moved to the political right, Vargas Llosa, 74, remains a tireless opponent of dictatorships around the world.

When he won his Nobel in October for a large body of work including historical novels, crime novellas, light-hearted comedies and academic essays, he was hailed by the jury for "his cartography of structures of power and his trenchant images of the individual's resistance, revolt, and defeat."