Berlin (AFP) - The first reprint of Adolf Hitler's "Mein Kampf" in Germany since World War II has proved a surprise bestseller, heading for its sixth print run, its publisher said Tuesday.

The Institute of Contemporary History of Munich (IfZ) said around 85,000 copies of the new annotated version of the Nazi leader's anti-Semitic manifesto had flown off the shelves since its release last January.

However, the respected institute said that far from promoting far-right ideology, the publication had enriched a debate on the renewed rise of "authoritarian political views" in contemporary Western society.

It had initially planned to print only 4,000 copies but boosted production immediately based on intense demand. The sixth print run will hit bookstores in late January.

The two-volume work had figured on the non-fiction bestseller list in weekly magazine Der Spiegel over much of the last year, and even topped the list for two weeks in April.

The institute also organised a successful series of presentations and debates around "Mein Kampf" across Germany and in other European cities, which it said allowed it to measure the impact of the new edition.

"It turned out that the fear the publication would promote Hitler's ideology or even make it socially acceptable and give neo-Nazis a new propaganda platform was totally unfounded," IfZ director Andreas Wirsching said in a statement.

"To the contrary, the debate about Hitler's worldview and his approach to propaganda offered a chance to look at the causes and consequences of totalitarian ideologies, at a time in which authoritarian political views and rightwing slogans are gaining ground."

- 'Not reactionaries or radicals' -

The institute said the data collected about buyers by regional bookstores showed that they tended to be "customers interested in politics and history as well as educators" and not "reactionaries or rightwing radicals".

Nevertheless, the IfZ said it would maintain a restrictive policy on international rights. For now, only English and French editions are planned despite strong interest from many countries.

The institute released the annotated version of "Mein Kampf" last January, just days after the copyright of the manifesto expired.

Bavaria was handed the rights to the book in 1945 when the Allies gave it control of the main Nazi publishing house following Hitler's defeat.

For 70 years, it refused to allow the inflammatory tract to be republished out of respect for victims of the Nazis and to prevent incitement of hatred.

But "Mein Kampf" -- which means "My Struggle" -- fell into the public domain on January 1 and the institute said it feared a version without critical commentary could hit the market.

Partly autobiographical, "Mein Kampf" outlines Hitler's ideology that formed the basis for Nazism. He wrote it in 1924 while he was imprisoned in Bavaria for treason after his failed Beer Hall Putsch.

The book set out two ideas that he put into practice as Germany's leader going into World War II: annexing neighbouring countries to gain "Lebensraum", or "living space", for Germans, and his hatred of Jews, which led to the Holocaust.

Some 12.4 million copies were published in Germany and from 1936, the Nazi state gave a copy to all newlyweds as a wedding gift.