A 1914 watercolour attributed to Adolf Hitler could fetch up to 50,000 euros when it is auctioned later this week, a German auction house chief said.

Auctioneer Kathrin Weidler said the painting entitled "Standesamt und Altes Rathaus Muenchen" (Civil Registry Office and Old Town Hall of Munich) is one of about 2,000 works Hitler painted from about 1905 to 1920 as a struggling young artist.

Asked about criticism that it is tasteless to auction the Nazi dictator's works, generally considered to be of limited artistic merit, Weidler said complaints should be addressed to the sellers - an unidentified pair of German sisters in their 70s.

Hitler wrote in his autobiography "Mein Kampf" that his hopes as a young man of becoming an artist were dashed by his repeated rejection by Vienna's Academy of Fine Arts.

Weidler Auction House in Nuremberg, where Hitler held mass Nazi party rallies from 1933 to 1938, said it had received inquiries from potential bidders in America, Japan and across Asia. Five other Hitler paintings previously auctioned fetched as much as 80,000 euros while others went for just 5,000.

A typed letter signed by Albert Bormann, brother of Hitler's private secretary, Martin Bormann, came with the painting as well as the original handwritten bill dated September 25, 1916, which Weidler said was a rarity for Hitler's art.

But that has raised doubt among critics about the painting's origins. They recall how hoaxer Konrad Kujau used supposed certifications of authenticity to trick some historians when he marketed what proved to be the bogus "Hitler's Diaries" in 1983.

The watercolour will be auctioned on Saturday (November 22).