BERLIN (AP) - The Huffington Post is expanding further with a German language edition, putting new pressure on media companies in Europe's largest economy as they struggle with newspaper closures and try to introduce online pay walls.

The online news portal said on Monday it is partnering with Tomorrow Focus AG, a division of Germany's Burda Media group, to launch the site this fall, featuring its "signature mix of news, blogging, community, and social engagement". A core editorial staff in Munich will produce the site, catering to readers in Germany, Austria and Switzerland - a market of about 100 million people - while offering free content and relying solely on advertisement revenue.

The Huffington Post already has international editions in Britain, Canada, France, Italy and Spain. A Japanese version is due to launch in May. The United States version of the site was founded by Arianna Huffington in 2005 and bought by AOL Inc for US$315 million (S$389 million) in 2011, though it has not turned a profit since.

Experts say the Huffington Post's arrival in Germany could prove disruptive for the established players in Europe's biggest news market.

"This is a big thing," said media studies professor Jo Groebel. "The leading German news websites still look and read like the extension of their printed parent media, but the Huffington Post's style is different. We have seen in the US how fast it rose to prominence," he added.

Mr Groebel said the Huffington Post's style will be a breach with German media tradition, which grants great prominence to political news coverage and seeks to distance opinion from factual reporting.

"Judging by the US site, the Huffington Post's reporting will be more emotional, more personality-driven, strongly focusing on cliffhangers and short news episodes," Mr Groebel said.

While other German online media might eventually follow that trend, experts say the bigger challenge might be Huffington Post's insistence on offering content for free. That could dent other media companies' hopes of erecting pay walls to make up for lost advertisement revenue in their core print business.

German publisher Axel Springer AG seeks to make users pay for content from its newspapers websites - which include the online offerings of daily Die Welt and that of mass-selling tabloid Bild - following a pay wall model championed by the New York Times.

Other German media groups are pursuing similar plans - but none has yet introduced a pay wall with commercial success.

Germany's leading news website, Spiegel Online, has so far rejected the idea of a pay wall. But that may change after a leadership shake-up on Monday that will see the head of German news agency dpa, Mr Wolfgang Buechner, take over news weekly Der Spiegel and its Website.

Germany's media industry is experiencing its most serious crisis since World War II, according to the DJV journalists' union.

The country's second-largest business daily, Financial Times Deutschland, was shut late last year and newspaper Frankfurter Rundschau filed for insolvency and laid off all but a core staff. German new agency dapd went bankrupt this year and most newspapers are currently seeking to cut costs amid falling advertisement revenues.

Newspaper readership in Germany has been falling constantly over the past few years. From 2000 to 2011 the daily circulation of all newspapers fell by about 22 per cent, from 24 million to 18.9 million copies, according to the BDZV lobby group of newspaper publishers.

Trends in the European newspaper industry appear to follow those set by their US peers, with falling revenues leading to paper closures as readers switch to read their news online or on tablet computers.

The Huffington Post's German cooperation partner sees a silver lining in the changing media landscape, saying its approach to giving readers more possibilities to contribute their own ideas will benefit the news segment.

"It offers our public a new way of experiencing journalism and enriches the German media landscape with fresh, unconsumed voices," said Tomorrow Focus managing director Oliver Eckert.