Imprisoned former high-ranking Nazi official Rudolf Hess, once one of Adolf Hitler's closest and most devoted associates, has not indicated knowledge that the German dictator kept a diary, an American ex-official said yesterday.

Retired U.S. Army Lt. Col. Eugene K. Bird, who served from 1964 to 1972 as American commandant of Spandau prison in West Berlin where Hess is being held, said Hess was the most likely of all Nazi functionaries to have known if Hitler kept a diary.

Bird told reporters in West Berlin that Hess, during the many hours of talks that Bird had with him, never mentioned that Hitler kept a personal account of his activities and thoughts.

Bird was forced to retire from the Army for violating rules that prohibited officials from discussing political matters with the seven major Nazi war criminals who were imprisoned in Spandau. He later wrote a book, "Rudolf Hess, Prisoner No. 7," about his talks with Hess.

Hess has emerged as a key figure in the growing controversy over the authenticity of the diaries and other documents attributed to Hitler that purportedly were hidden in a hayloft in what is now East Germany for more than 30 years. The West German magazine Stern says it found the diaries after a 2 1/2-year search in Europe and South America.

Prominent historians have voiced skepticism about the authenticity of the documents.

Hess' son, Wolf-Ruediger Hess, who visited his father on his birthday, has urged authorities to permit the elder Hess to examine the documents to determine their authenticity. Peter Koch, editor of Stern, who maintains the diaries have been authenticated by experts, also urged an examination by the prisoner