The abuses – confirmed on Thursday – occurred while Iraqi detainees were interrogated earlier this year in southern Iraq.
"This case covers four interrogations of Iraqis arrested at Camp Eden in [the] Basra area between March and June 2004," investigators said in a statement.
"The prisoners were forced to take up stressful and painful postures and kept that way by force."
Though the investigators found no evidence of physical torture, they said the detainees "were verbally humiliated, for example by being addressed in a way particularly insulting to Muslims".
"During these interrogations, they were to a certain extent also refused food, water and access to toilets," they said.
The investigators said they also suspected that the command of the Danish battalion serving in Iraq had "to a certain degree approved of these interrogation conditions and failed to intervene immediately or to order an enquiry into the case".
Peter Otken, special consultant to the investigative body, said a woman officer, Annemette Holm, had been charged under article 15 of the Danish military penal code for dereliction of duty, punishable by up to three years in jail in wartime or one year in peacetime.
Defence Minister Soeren Gade on Tuesday had ordered the immediate recall of Henrik Flach, the commander of the Danish contingent in Iraq, together with three senior officers.
Flach said on television that Holm had "gone beyond the limits in her interrogation methods".
But he said what had happened in his unit had been "a long way from the torture inflicted by American soldiers on Iraqis in Abu Ghraib jail".