Decrying the 2004 winner's award-winning book as "violent pornography", academician Knut Ahnlund's resignation and criticism of Austrian author Elfriede Jelinek appeared timed to gain maximum impact.
In a signed newspaper article, Ahnlund said giving the prize to Jelinek - which surprised even Austria - "caused irreparable harm to the value of the award for the foreseeable future".
He called Jelinek's writing "whingeing, unenjoyable, violent pornography".
Ahnlund did not explain why he had waited a year after the prize went to Jelinek to quit, but academy head Horace Engdahl suggested it was timed to spoil this year's announcement.
"This very possibly has something to do with the fact that this week the academy will announce this year's winner," Engdahl said. There was no immediate response from Jelinek.
The world's top literary award, worth $1.3 million and given by the Swedish king in December, is usually announced on one of the first two Thursdays in October.
Unlike the Nobels for peace, medicine, physics, chemistry and economics, the literature prize date is only announced two days beforehand. The website said on Tuesday that it was scheduled for Thursday afternoon.
But the lack of news last week gave rise to speculation the 18 academy members were split, with a British paper reporting that the divisive choice was Turkish novelist Orhan Pamuk.
Favourites for prize
Bookmaker Ladbrokes makes Syrian poet Adonis the two-to-one favourite followed by US novelist Joyce Carol Oates and poets Tomas Transtromer of Sweden and South Korean Ko Un.
Belgian poet Hugo Claus, American novelist Philip Roth, Italians Claudio Magris and Antonio Tabucchi, Czech novelist Milan Kundera, Indonesian novelist Pramoedya Ananta Toer and Dutch poet and novelist Cees Nooteboom are also tipped.
The academy, which has awarded the prize founded by dynamite millionaire Alfred Nobel since 1901, never leaks its shortlist.
South African John Maxwell
Coetzee was the 2003 winner
A rare indication of scandal inside the ivory tower of the academy came with the news of Ahnlund's resignation. "After this I cannot even formally remain in the Swedish Academy," he wrote.
Inactive at academy
Engdahl said Ahnlund had not been active in the academy for nearly 10 years and was not privy to the Jelinek prize debate.
"He knows nothing about the discussion that led to the choice of Elfriede Jelinek so what he says in this article of his must be seen as empty speculation," Engdahl concluded.
The choice of Nobel laureates is often dismissed as obscure when the winner comes from outside the publishing mainstream of Anglophone authors translated into dozens of languages.
South African JM Coetzee - whose novels written in English are widely read - was a popular choice in 2003.