The publishers have brought forward the release date and German bookshops are struggling to keep up supplies.

Such is the demand for Gunter Grass's autobiography, which has stunned Germany with revelations that the Nobel-prize winning novelist once served in Hitler's Waffen SS as a teenager.

Grass, 78 - regarded by many as Germany's moral arbiter - recounted the secret shame that has weighed upon him for decades following his involvement in the elite military force, in a pre-publication interview with a German newspaper last weekend.

His admissions ignited furious debate across the country, with calls that he be stripped of his literary awards and of his honorary citizenship of the Polish port of Gdansk, where he was born. Lech Walesa, the former president of Poland and a Nobel peace laureate, said today that he might renounce his own honorary citizenship of Gdansk if Grass keeps his.

Far from affecting sales, the controversy has rapidly whipped up interest in his memoirs, entitled Peeling Onions. Steidl, the publisher, has now delivered 130,000 books out of a print run of 150,000. A reprint of a further 100,000 is hastily being carried out, and the timetables for publishing translated copies are being brought forward.

"It’s astonishing," said Bianca Kroemer, spokeswoman for Berlin’s Dussmann bookshop. "By the end of the first day a quarter of our stock had gone – that’s due to the SS story."

Grass won international acclaim upon publication in 1959 of his first novel, The Tin Drum, which is set in Gdansk. He fast became the country’s best known post-war writer, producing sprawling literary accounts of life in Nazi Germany which encouraged Germans to confront their past.

Last night he gave a television interview in which he confessed more about how he had fallen under the sway of national socialism during the early war years. The author said the Nazis made a big impression on him from the age of 13, and he had thought that joining the Waffen SS would provide a direct route to Hitler.

"I was caught up in the ideology," he said. "I was blinded by it. I wanted to be a hero and perhaps play some sort of role."

But the reality of fighting on the eastern front was very far from his dreams. Peeling Onions contains graphic descriptions of combat and the fear he experienced. "I see myself crawling under a tank, as I had been taught... Beset by fear, I wet myself," he writes.

"Bodies lay scattered, alone and piled up, dead, alive, contorted, skewered by branches, dusted by grenade splinters."

The Waffen SS was a highly-trained Nazi combat unit, initially comprising volunteers, which participated in the Holocaust. By the end of the war, however, most members were drafted and many were under 18.

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