It had been temporarily closed for installing the new Zarih (outer sarcophagus enclosure) of the holy shrine, al-Kafil news network reported.
The new golden Zarih has been built by Iraqi artists and will be officially unveiled at a ceremony on Wednesday.
A number of senior guests from Iraq and other countries will attend the ceremony, which will be held on the occasion of birth anniversary of Imam Ali (AS).
Millions of pilgrims from around the world visit the holy shrines of Imam Hussein (AS) and Hazrat Abbas (AS) in Karbala every year.
In recent years the shrines have undergone a series of enhancements and additions.