According to Baghdad al-Yawm news website, a police spokesman said on Friday that police and security forces have managed to thwart the plots.
Qalib Atiya added that remnants of the Daesh (ISIL or ISIS) terrorist group had planned the attacks.
He went on to say that more than 20,000 police and security forces have been mobilized to ensure the security of the pilgrims.
Arbaeen comes 40 days after Ashura, the martyrdom anniversary of the third Shia Imam, Imam Hussein (AS).
Each year, a huge crowd of Shias, including Iranians, flock to Karbala, where the holy shrine of Imam Hussein (AS) is located, to perform mourning rites.
In the past few years, around 20 million pilgrims from all over the world took part in the mourning ceremonies in the Iraqi holy city marking Arbaeen.
This year, Arbaeen falls on Tuesday, October 30.
Daesh has made attempts to target Arbaeen pilgrims in recent years.