A Danish military intelligence officer and four military police sergeants have denied abusing 11 prisoners while they were based in southern Iraq.
Capt Annemette Hommel was sent home early from Iraq
The trial in Denmark heard that Capt Annemette Hommel forced prisoners to kneel during lengthy interrogations and refused to give them food and water.
The military prosecutor said the four police sergeants also verbally humiliated the detainees.
If found guilty, the five could each face a year in prison.
Capt Hommel is charged with four counts of negligence while on duty in March, April and June 2004.
All five are accused of verbal abuse of detainees.
Denmark has about 500 troops in southern Iraq, near Basra, and most people support their government's backing of the US-led coalition in Iraq.
Capt Hommel, 37, who was ordered to return home from Iraq before her tour of duty ended, said she had done nothing wrong.
Last year, she said the allegations stemmed from a misunderstanding with the Palestinian translators working at the camp, who had objected to her interrogation techniques.
The French news agency AFP says the trial will follow the Danish military code, but the judge and defence lawyers will be civilians. The prosecutor will represent the military.
A verdict is expected in December.