STOCKHOLM (Reuters) - Judges who award the Nobel prize for literature have long been suspected of courting the controversial or obscure just for the sake of it, but the head of the selection panel said merit is the sole consideration.

The Swedish Academy announces the winner of the world's top literary prize, founded by dynamite millionaire Alfred Nobel, along with four other awards, on a Thursday in October.

In the same vein, the academy has tended to surprise with its choices. The 2005 winner, British playwright Harold Pinter, was well known but seen as controversial because of his strong criticism of the U.S.-led war in Iraq.

The 2004 laureate, reclusive Austrian feminist novelist Elfriede Jelinek, was at once obscure and polarizing for her stark depictions of power in sex and human relationships.

"It is difficult to know what people expect, and it has little relevance to the slow, painstaking labor of reading and judging that the Academy performs," Academy head Horace Engdahl told Reuters in a recent interview.

The Academy never reveals its shortlist and the names of the few hundred nominees the literature committee usually receives -- by invitation only -- will stay a secret for five decades.

According to British betting outfit Ladbrokes, this year's front-runners include Turkish writer Orhan Pamuk, Syrian-Lebanese poet Adonis, Polish author Ryszard Kapuscinski and American novelists Joyce Carol Oates and Philip Roth.

Even though only one of the Ladbrokes favorites has so far won, South African novelist J.M. Coetzee in 2003, spokesman Robin Hutchison pointed out that it has only been taking wagers on the prize for three years.

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