Foreign Ministry spokeswoman Amelie Heinsjo says the man has been held as a security detainee since May.
She says Sweden has presented "a demand for a legal process and that he is given a public defense counsel, or that he is released."
Heinsjo gave no other details about the case Monday.
Newspaper Norrkopings Tidning reports the man became a Swedish citizen after moving from Iraq in 2000. It says he returned to Iraq in May to start a construction business.
The U.S. interprets the U.N. Security Council resolution that authorizes the Iraq mission as giving the coalition broad powers to detain anyone believed to pose a security threat.