Confirmed cases of H1N1 swine flu infection in Germany have more than doubled in the past week, the Robert Koch Institute (RKI) for infectious diseases said.

We now have more than 15,000 reported new cases per week -- and those are just the ones confirmed in the laboratory, the RKI's Gerard Krause told ZDF television on Monday.

Last Wednesday the institute said about 7,000 new cases were being identified in Europe's largest economy per week.

As of last week, 16 people had died from the flu in Germany, with more than 50,000 infected, according to the institute.

The H1N1 virus has spread to over 200 countries, and caused more than 6,250 deaths to date, mostly in the Americas region, according to the World Health Organization.