The German government said Wednesday it was "very concerned" by Israel's designation of six leading Palestinian civil society groups as outlawed "terrorist organisations", in a move also criticised by the UN.
The Jewish state said its decision last week was due to their alleged financing of the Popular Front for the Liberation of Palestine (PFLP).
It accused the six of working covertly with the leftist militant group, which pioneered plane hijackings in the 1970s to highlight the Palestinian cause and is blacklisted by several Western governments.
"We are very concerned by the Israeli decision," a German foreign ministry spokeswoman told reporters, saying that the groups' placement on a terror list would have "broad political, legal and financial implications" for them.
The German government routinely conducts "reviews of accusations and indications of connections of possible partners to terrorist organisations", she added.
"We are waiting for further information from the Israeli government" on its justification for the move, the spokeswoman said.
The UN human rights chief Michelle Bachelet on Tuesday called the Israeli decision an attack on freedoms of association, opinion and expression and on the right to public participation.
Germany and Israel forged strong diplomatic ties in the decades after World War II, with Berlin committed to the preservation of the Jewish state in penance for the Holocaust.
Throughout her 16 years in power, Chancellor Angela Merkel has described Israel's national security as a crucial priority in German foreign policy and vowed continuity by future governments on a visit to Jerusalem this month.