Jorge Luis Borges was possibly the greatest Spanish-language writer of the 20th century, but the Chilean author Eduardo Labarca felt the best tribute a fellow writer could pay would be to urinate on his tomb.

A photograph on the cover of 72-year-old Labarca's latest book appears to show him doing exactly that in the Geneva graveyard where Borges's well-tended, flower-adorned tomb lies.

The photo has provoked outrage in Borges's native Argentina, even though Labarca admits the stream of water descending on the great man's grave actually came from a bottle of water hidden in his right hand.

"This is in bad taste and is a violation," said the Argentine culture minister, Jorge Coscia. "You don't gain anything by urinating on a tomb."

Labarca was unapologetic today about the cover to his book The Enigma of the Modules, saying it could best be understood by reading the work itself.

"Peeing on that tomb was a legitimate artistic act," he told the Guardian. "The cover of the book is coherent with the contents and is best understood through that."

Labarca is a translator, writer and journalist who went into exile and worked for a Soviet radio station after the coup d'état that overthrew Salvador Allende and brought in the dictatorship of General Augusto Pinochet. He went on to work as a translator for various United Nations organisations and currently splits his time between Vienna and Chile.

"I am not just a person who goes around peeing on tombs, but a writer with a serious oeuvre," he said today.

Labarca told Argentina's perfil.com that Borges's talent as a writer had not been matched by his behaviour outside literature.

"Anyone who is offended by this is very short-sighted," he said. "Borges was a giant as a writer but I feel complete contempt for him as a citizen. As an old man, almost blind, he came to meet the dictator Pinochet in the days when he was busy killing."

Borges was delighted with Pinochet. "He is an excellent person," he said afterwards. "The fact is that here, and in my country and in Uruguay, liberty and order are being saved."