Israeli Prime Minister Benjamin Netanyahu spoke with relatives of two hostages held in Gaza seen in videos released by Palestinian militant groups, expressing his "profound shock" over the images, his office said.

Since Thursday, Hamas and its ally Islamic Jihad have released three clips showing two hostages taken during the October 7, 2023 attack on Israel that triggered the ongoing conflict in Gaza.

The images of Rom Braslavski and Evyatar David, looking emaciated after nearly 22 months of captivity, have sparked strong reactions among Israelis, fuelling renewed calls to reach a truce and hostage release deal without delay.

In the footage shared by the Palestinian Islamist groups, 21-year-old Braslavski, a German-Israeli dual national, and 24-year-old David both appeared weak and malnourished.

The videos make references to the dire humanitarian conditions in Gaza, where UN-mandated experts have warned a "famine is unfolding".

Netanyahu, according to his office, spoke "at length" with Braslavski and David's families on Saturday, decrying "the cruelty of Hamas" and accused the group of "deliberately starving our hostages" and documenting them "in a cynical and evil manner".

Braslavski and David are among 49 hostages captured during Hamas's 2023 attack who are still being held in Gaza, including 27 the Israeli military claims are dead.

Most of the 251 hostages taken in the attack have been released during two short-lived truces in the conflict, some in exchange for Palestinians in Israeli custody. (AFP)