The federal government sees it as "a possible path", according to an answer to a parliamentary query, the Welt am Sonntag newspaper reported.
Several of Germany's 16 states had also signaled support in principle for the idea which would mirror Germany's voluntary Christian "church tax", the rnewspaper said.
Concern has grown in Germany about the influence of foreign funding sources on mosques for the country's estimated five million Muslims, who hail mostly from Turkey and Arab countries.
Some 900 mosques in Germany are run by the Turkish-Islamic Union of the Institute for Religion (Ditib), under the authority of President Recep Tayyip Erdogan's government.
Its imams are paid by the Turkish state, and the group has come under scrutiny with some of its members suspected of spying on Turkish dissidents living in Germany.