The Israeli government has begun rounding up migrants in order to forcibly deport them.
Israeli authorities said they had arrested 45 people from South Sudan and several others from Africa and Asia.
A journalist described how migrants had been arrested on the street, at work and in door-to-door searches.
News of the arrests brought hundreds of people onto the streets of the Israeli capital Tel Aviv.
Protesters chanted, “An African is a human being.”
An Israeli court has decided that around 1,500 migrants from South Sudan would no longer be at risk if they return there.
Migrants can be held in Israeli prisons for up to three years without charge.
Israel is also threatening Israelis who house, employ or transport migrants with five-year jail terms.
The government has drawn up draft legislation that is expected to have a preliminary hearing this week.
Meanwhile Palestinian prisoners are continuing their hunger strike in Israeli jails. They demand better conditions and an end to the practice of “administrative detention” without trial.