The Knesset this week passed a first reading of a new law mandating harsher prison conditions for Hamas members.

The measure, which was supported by the government, has been nicknamed the "Shalit Law" in reference to captured Israeli soldier Gilad Shalit who is being held by Hamas in Gaza.

Proposed by Likud MK Danny Danon, the legislation will allow prison authorities to deny Hamas prisoners rights they have enjoyed until now, including family and conjugal visits, academic studies and watching television.

Visits by their lawyers and International Red Cross officials will continue, despite the fact that Gilad Shalit has not been visited by the Red Cross since his capture. The government decided to support the law after Hagai Hadas, its chief negotiator for the Gilad Shalit prisoner deal, said that it could spur Hamas leaders to reach an agreement.

Hamas has yet to respond to Israel's latest list of 450 Hamas prisoners whom it is prepared to release in exchange for the captive soldier. The list was handed to Hamas six months ago via the German mediator Gerhard Conrad, but talks have ground to a standstill, due mainly to Israel's opposition to releasing a number of "high-value" prisoners and disagreement within the Hamas leadership.

Next month it will be four years since the attack on the Kerem Shalom outpost near the Gaza border in which two soldiers were killed and Gilad Shalit was taken prisoner.

It is still unclear how the law will be implemented - whether the prison commanders will have discretion over which prisoners will forfeit their rights or if there will be a blanket clampdown.

A government source said that the law was "primarily a message to Hamas that they can't drag their feet forever over Gilad Shalit".

A Hamas spokesman in Gaza responded by saying that "this is an attempt by Israel to blackmail us into releasing Shalit for free".