Spokeswoman Aimée van Baalen called on all citizens to join protest marches in many cities next Wednesday.
A demonstration was already scheduled to take place in Berlin this Wednesday.
A total of 15 properties, including flats and offices, were searched on Wednesday morning in a raid connected to several criminal charges against members of the group.
"The 15 house searches have hit all supporters hard. They make us afraid but we must not remain in this fear," van Baalen said.
"Do we in Germany have to experience a drought, suffer from food shortages... before we understand that the Last Generation stands up for all of our lives and that this is not criminal?"
The climate protection group wants to continue its resistance, she added.
German Interior Minister Nancy Faeser has defended the raids, saying the rule of law cannot be made a mockery of.
"The police and judiciary do not accept criminal offences, but act - as is their duty," Faeser told the Funke media group on Wednesday.
Chancellor Olaf Scholz recently said that he thought it was "completely nutty to somehow stick yourself to a painting or on the street".
Leading figures with the environmentalist Green party, part of his governing coalition, have also said the group's actions are counterproductive.
with AP
