The criticism is "irrelevant and unfounded," said Böhmer, a member of Angela Merkel's conservative Christian Democrat Union (CDU), on Wednesday in Berlin.
Members of the centre-left Social Democrats (SPD), the pro-business Free Democrats (FDP), and the environmentalist Green party have all expressed reservations about the test.
"Those who want to be German and have all of the corresponding rights of German citizens, particularly the right to vote, should at least have a basic command of the structure and mechanisms of our country," Böhmer said, adding that naturalization tests are an "important symbol of integration" and an "absolute matter of course" that other countries also require.
The multiple choice tests covering geography, history, politics and society were developed by the Humboldt University in Berlin, and will be obligatory beginning September 1, 2008, the Interior Ministry said Tuesday.
Naturalization candidates will be tested on 33 of 310 possible questions, and must answer at least 17 questions correctly to pass. The test will cost €25, and can be taken as many times as candidates wish.