Doctors Without Borders (MSF) has denounced the "extremely precarious" situation of Palestinians displaced by the ongoing Israeli military onslaught in the occupied West Bank.

According to the United Nations, some 40,000 residents have been displaced since January 21, when the Israeli army launched a military incursion in the north of the territory.

The West Bank, occupied by Israel since 1967, is home to about three million Palestinians as well as nearly 500,000 Israelis living in settlements that are illegal under international law.

The Israeli onslaught started two days after a truce agreement came into effect in Gaza between the Israeli military and the Palestinian resistance group Hamas.

The situation of the displaced Palestinians is "extremely precarious,” said MSF, which is operating in the area.

Palestinians "are without proper shelter, essential services, and access to healthcare,” the NGO said.

"The mental health situation is alarming."

MSF said the scale of forced displacement and destruction of camps "has not been seen in decades" in the occupied West Bank.

"People are unable to return to their homes as Israeli forces have blocked access to the camps, destroying homes and infrastructure," said MSF Director of Operations Brice de la Vigne.

"Israel must stop this, and the humanitarian response needs to be scaled up."

Dubbed "Iron Wall,” the Israeli onslaught is primarily targeting three refugee camps, Jenin, Tulkarem, and Nur Shams, and Defence Minister Israel Katz said in February it would last several months.

"I have instructed them to prepare for a prolonged stay in the evacuated camps for the coming year and not to allow the return of their residents or the resurgence of terrorism," he said in a statement.