The Palestinian Prisoners Society said the prisoners had staged the hunger strike in protest against a recent decision by Israeli prison authorities to place some Palestinian prisoners in solitary confinement.
Last week, Israel's Prison Service had taken steps to quell the strike by transferring some strike leaders to the southern Israel prisons of Ktziot, Nafha and Raymond, the NGO said.
It added that on Sunday morning, the Ktziot Prison administration informed 45 of the striking prisoners that they would be transferred, refusing to notify them about the new destination.
The Raymond Prison administration also informed 30 prisoners that they would be transferred, asking them not to take any of their belongings with them, the Palestinian Prisoners Society said.
Israeli authorities could not be reached for an immediate comment
Around 7,000 Palestinians in total are in Israeli jails, including 16 women and 250 children, the society said in a previous statement.