The Knesset plenum gave initial approval on Wednesday to a bill that would make it a crime to publicly deny Israel's right to exist as a Jewish state, punishable by a sentence of up to a year in prison.

The measure was the latest of several introduced in the past week by right-wing lawmakers and denounced by critics as an assault on free speech, particularly for Israeli Arab citizens, most of whom are of Palestinian origin.

It would outlaw the publication of any "call to negate Israel's existence as a Jewish and democratic state, where the content of such publication would have a reasonable possibility of causing an act of hatred, disdain or disloyalty" to Israel.

Forty-seven MKs voted in favor of the bill and 34 voted against, with Knesset Speaker Reuven Rivlin (Likud) abstaining from the vote.

MK Zevulun Orlev, a lawmaker with the right-wing Bayit Hayehudi party who initiated the bill, said the bill permitted a maximum one year prison term for any offenders.

The measure would have to pass three additional votes in parliament and a committee review before becoming law.

Orlev linked the bill to the case of former MK Azmi Bishara, who resigned from the Knesset and fled Israel in 2007 to avoid charges of assisting the enemy. Bishara was under fire then for a series of trips he had made to Syria and Lebanon, where he issued praise for Hezbollah.

Orlev said Bishara's case shows that what begins with words "very quickly leads to actions."

MK Haim Oron (Meretz) attacked the proposal, saying "this insane government, what exactly are you doing? Creating a thought police? Have you run off the rails?"

Oron said that even though he disagrees with those who do not support Israel's identity as a Jewish, democratic state, there is no reason to make it a criminal issue.

Civil rights activists have cautioned that this and other legislation threatens to curb the rights of Arab citizens.

Its approval on a preliminary reading showed how Israeli support for laws seen as targetting Israeli Arabs has grown since a right-wing government was sworn in after a February election.

Most Israeli Arabs, who make up about a fifth of Israel's population, are descended from Palestinians who remained in the country after hundreds of thousands either fled or were driven away in fighting over Israel's founding in 1948.

Many are related to Palestinians in conflict with Israel living in the Gaza Strip and occupied West Bank.

Naomi Chazan, president of the liberal New Israel Fund, denounced a bill approved by Israel's cabinet on Sunday to outlaw public displays of mourning over Israel's birth, which Palestinians call "nakba", an Arabic word for catastrophe.

Chazan called that bill an "attempt to trample on the feelings of pain of Israeli Arabs" that could hurt efforts to forge better coexistence between Jews and Palestinians.

Another bill introduced by Foreign Minister Avigdor Lieberman's Yisrael Beitenu Party this week would require Israeli citizens to take a loyalty oath to the Jewish state before they could be issued a national identity card.

The cabinet was scheduled to debate the loyalty oath measure at a session next week.