The arrests were made during home raids and at military checkpoints and included those compelled to surrender under pressure and those taken as hostages, the Palestinian Prisoners Society and the Commission of Detainees Affairs said in a joint statement.
Thirty arrests were recorded on Thursday, while the total number of arrests on Wednesday to Thursday night reached 40, they said.
Israeli forces carried out extensive acts of torture, brutal beatings and threats against detainees and their families, along with widespread acts of vandalism and destruction in Palestinian homes during the arrest campaigns, the NGOs said.
Tensions have been running high across the West Bank amid an Israeli military onslaught on the Gaza Strip following a cross-border attack by the Palestinian group Hamas on Oct. 7.
Israel and Hamas agreed early Thursday to extend a humanitarian pause in the Gaza Strip for another day to continue releasing hostages.
It had been set to end Thursday morning.
Since the initial pause began last week, 66 Israeli prisoners have been released over the course of six days in exchange for 210 Palestinians.