"We will start by examining human remains, then we will take DNA samples - DNA - and compare them with the database collected from the families," Zeid al-Yousuf, director general of the department, told AFP.
The doctor pointed out that "this work is a joint effort between the Martyrs Foundation and the Directorate of mass graves and cadres of medical justice with the organization of the International Committee for Missing Persons in addition to the international team of the United Nations."
In 2014, the Da'id organization killed scores of Yazidis in Sinjar in Nineveh province, tens of thousands of them were forced to flee, while thousands of girls and women were taken captive.
More than 6,400 Yezidis were abducted, of whom 3200 escaped, some were rescued, and the fate of others remains unknown.
According to the United Nations, evidence suggests that hundreds of Kujou villagers in Sinjar were killed by an uprisings, while more than 700 women and children were abducted.
The United Nations began its joint investigation last year, to extract the first bodies of the victims of Dahesh around the town of Kuju in March.
Last month, it said it had snatched 12 out of 16 sites identified around Kojo.
But Yusuf said the next stage of identifying the remains of the victims would be a very difficult process.
"We took about 1280 samples from families in Sinjar, but the problem is that many families have one survivor and the rest is missing," he said.
Many of the Yazid women who kidnapped them managed to escape during the organization's reign, but thousands remained unaccounted for.