BERLIN (Reuters) - Germany on Tuesday voiced alarm at reports that a political consultancy hired by Donald Trump improperly accessed information on 50 million Facebook users, and lawmakers demanded answers from the company and the government.

Germany's data privacy commissioner Andrea Vosshoff said she had no independent information to verify the reports, but the incident underscored the need for stronger privacy regulations.

U.S. and European authorities this week said they were investigating reports by the New York Times and Britain's Observer newspaper that Cambridge Analytica, a political consultancy, harvested users' personal data to support Trump's 2016 presidential election campaign.

The reports have depressed Facebook shares, and are fuelling calls for more regulation in Germany, where Facebook already faces an anti-trust inquiry and a tough new hate crime law.

"If the reports are proven true, this would be an alarming example of the risks of profiling on the Internet, something that this office and other privacy protection authorities have been warning about for years," Vosshoff said in a statement.

Justice Minister Katarina Barley told the Passauer Neue Presse newspaper that Facebook needed to take responsibility and explain how it planned to better protect the privacy of its users in the future.

She told the paper that users needed to know what would become of their data before consenting to its use. "Facebook must adhere to this legal basis. It is time for the company to take clear responsibility," she told the newspaper.

Privacy rights are a particularly sensitive and emotional issue in Germany after decades of state surveillance carried out by the Nazi regime, and later in Communist East Germany.

Germany's anti-trust regulator last month opened an inquiry into online advertising, responding to concerns expressed by advertisers and publishers about the "significant" market position of U.S. platforms Google and Facebook.

In December, the Federal Cartel Office also accused Facebook of abusing its dominant position to collect the personal data of its 2 billion users worldwide.

Facebook is also grappling with a new law under which the company and other social media sites can be fined up to 50 million euros if they fail to promptly remove hateful messages.

Chancellor Angela Merkel's conservatives and the Social Democrats called on Tuesday for an extraordinary session of the German parliament's digital committee to debate the latest reports, conservative lawmaker Thomas Jarzombek said.

"We want to question Facebook about whether German users were also affected, and whether a comparable mechanism could endanger the data of German users," he told Reuters.

Patrick Sensburg, another conservative lawmaker, called for "much harder sanctions" against Facebook and said the EU should consider financial penalties. "The German government and the EU must demand that Facebook provide comprehensive answers and informs those affected," he told German daily Bild.

(Additional reporting by Andreas Rinke; Editing by Paul Carrel/Mark Heinrich)

By Andrea Shalal