By Andreas Rinke

BERLIN (Reuters) -German right-wing conservative group Werteunion (Values Union) said on Saturday it had decided to found a new political party, adding to a fragmentation of the previously stable spectrum of parties in the country.

Members of the group gave Chairman Hans-Georg Maassen, in a closed party meeting in the city of Erfurt, a mandate by a large majority to initiate the founding of a "conservative-liberal" party, according to a statement from the group. Maassen is a former domestic security official popular with anti-immigration voters.

The party will be founded quickly so it can take part in state elections in Thuringia, Saxony and Brandenburg in September. The move could come as soon as February, according to sources with knowledge of the matter.

With the creation of new parties, Germany's political landscape risks splintering further following the formation of Alternative for Deutschland (AfD) 11 years ago, which has taken votes away from traditional heavyweights such as the SPD (social democrats) and CDU (conservatives).

Sahra Wagenknecht, a well-known figure in Germany's far left, also launched her own party in early January.

Members of the Werteunion took part in a recent conference with right-wing extremists in Potsdam.

(Reporting by Andreas Rinke; writing by Emma-Victoria Farr; Editing by David Holmes)