Right-wing lawmakers in the southern German state of Baden-Wuerttemberg on Tuesday rejected calls to expel a party member facing accusations of anti-Semitism, instead launching a review of his articles and books.

The Alternative for Germany (AfD) party has caused outrage in the political mainstream with critical remarks about Muslims and immigrants, but has gained in opinion polls due to public disquiet over the government's open-door policy for refugees.

Wolfgang Gedeon, a former doctor turned AfD politician, has said that denying the Nazi Holocaust, in which 6 million Jews were killed, is a legitimate expression of opinion. Holocaust denial is a crime in Germany.

The AfD's parliamentary group in Baden-Wuerttemberg voted to suspend Gedeon's membership pending an independent review of his written work, disregarding a call by AfD Co-Chair Joerg Meuthen for him to be kicked out of the party.

Josef Schuster, president of the Central Council of Jews in Germany, criticised the decision. "Wolfgang Gedeon's (work) is anti-Semitic and written with the clear intent to stir up hatred against the allegedly all-dominant Jews," Schuster said.

Last month, AfD Vice Chair Alexander Gauland caused a storm when he said people in Germany would not want to have national soccer star Jerome Boateng, born in Berlin to a Ghanaian father, as their neighbour.

AfD leader Frauke Petry apologised to Boateng, but herself stirred controversy earlier this year when she suggested police be given powers to use firearms against illegal immigrants.

The AfD now commands about 15 percent in national opinion polls thanks to popular unease over the admission of more than 1.1 million mainly Muslim migrants over the past year. The AfD is now represented in eight of 18 regional state assemblies.