"I'm 86 now. I don't think I will manage another novel," Grass told the regional daily Passauer Neue Presse in a pre-released interview to appear on Monday.
"My health does not allow me to take on projects that will last five or six years and that would be the amount needed to research a novel," added Grass.
He said he was devoting his time now to drawing and painting with watercolours. From this "creative activity", some "first texts" have already been produced, he said.
Grass achieved world fame with his debut novel, "The Tin Drum" in 1959, and has pressed his country for decades to face up to its Nazi past.
But he saw his substantial moral authority undermined by his 2006 admission, six decades after World War II, that he had been a member of Hitler's notorious Waffen SS as a 17-year-old.
He landed in hot water in 2012 when he penned a poem called "What must be said", in which he said he feared a nuclear-armed Israel "could wipe out the Iranian people" with a "first strike".
This sparked outrage both at home and abroad and he was declared persona non grata in Israel.