Lenz captured some of his country's most prestigious prizes for novels such as the widely translated "Deutschstunde" (German Lesson), "Das Vorbild" (An Exemplary Life) and "Heimatmuseum" (The Heritage).
His publisher throughout his five-decade-long career, Hoffmann und Campe, called him in its obituary "one of the most important and most-read writers in German literature".
Lenz was an impassioned participant in the intellectual life of his era, and held lively debates with luminaries such as Nobel laureate Gunter Grass and poet and Holocaust survivor Paul Celan.
"Siegfried Lenz was one of these people you don't find anymore – a writer who is loved beyond the community of literature aficionados," Daniel Kampa of Hoffmann und Campe said in a statement.
He was an "artist who saw his writing as a moral duty and who engaged with world events," Kampa added.
"German Lesson", published in 1968, in particular laid bare how Nazi ideology infected a culture that had prided itself on its refinement and sophistication.
Although Lenz was widely revered for injecting a moral conscience into the literature of the post-war period, he himself expressed frustration about the limited impact of books on Western society.
"As a writer I learned how little literature is capable of, how meagre and unpredictable its effect was and still is," Lenz said as he accepted the peace prize of the German Publishers' Association in 1988.
Born in Lyck in East Prussia in 1926, Lenz was called up to serve in Hitler's navy before deserting in April 1945.
After a brief period as a prisoner of war, Lenz moved to the northern port city of Hamburg to study philosophy and literature.
He became active in the Social Democratic Party and developed a friendship with Helmut Schmidt, who was chancellor of West Germany from 1974 to 1982, that would last more than 50 years.
The cause of his death was not released.
SEE ALSO: Gunter Grass hangs up novelist pen