Chancellor Angela Merkel says Germany plans to increase its troop numbers in Afghanistan by 500 to help train Afghan security forces and protect the civilian population.
Germany currently has about 4300 soldiers in northern Afghanistan - the third-largest foreign contingent after the United States and Britain.
The deployment will need parliamentary approval. German MPs are due to debate the issue on Wednesday.
The announcement comes two days before an international conference in London on the future of the Afghan mission.
As well as the 500 extra troops, Mrs Merkel said Germany will prepare a "flexible reserve" of 350 soldiers who could be deployed to Afghanistan for a limited time.