Israeli MPs were on Wednesday to vote on a controversial law that would see parliament set up committees to investigate human rights groups accused of anti-Israel activity.
The bill, sponsored by hardline Foreign Minister Avigdor Lieberman's Yisrael Beitenu party, was expected to fail after Prime Minister Benjamin Netanyahu said he would not support it.
The law calls for the establishment of parliamentary inquiry committees to investigate foreign funding of leftwing non-governmental organisations (NGOs).
Introducing the bill to the Knesset, Yisrael Beitenu MP Faina Kirshenbaum on Wednesday accused such NGOs of helping groups who actively sought to harm Israel.
"We are fighting the ongoing delegitimisation of Israel," she said. "All of us feel there is a problem here."
But she sought to reassure opponents that the bill would not lead to a political witch hunt.
"We are going to research these groups, not investigate them. We don't want the Knesset to replace the police," she said.
However, opposition leader Tzipi Livni roundly condemned the initiative.
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"This evil initiative, with its anti-democratic message, harms the democracy of the state of Israel," Livni said, adding that, even if the bill passed, her Kadima party would boycott such committees.
As MPs debated the issue ahead of the evening vote, speakers both for and against were frequently interrupted by heckling, with more than 50 parliamentarians tabled to speak in the debate.
Earlier this week, Lieberman created a stir after he denounced several of the groups in question as "terror organisations," saying they were undermining Israel's legitimacy and helping foreign efforts to charge its soldiers with war crimes.
"We're not talking here about leftist organisations and not about human rights groups, we're talking about terror organisations," he said on Sunday.
He pointed the finger at groups such as Adalah, which lobbies for Palestinian legal rights, and Breaking the Silence, which encourages soldiers to speak out about abuses committed inside the Palestinian territories.
In a statement ahead of the vote, the Association for Civil Rights in Israel (ACRI) condemned the bill, saying it was part of a trend aimed at isolating and undermining groups critical of the government.
"ACRI condemns the initiative, which is perceived as part of a broader, ongoing delegitimisation and harassment campaign waged by the current government against Israeli human rights organisations," it said.
Netanyahu has expressed opposition to the bill and has said he would not not impose coalition discipline for the vote.
The prime minister said any allegations of improper behaviour by the rights groups should be probed by the police under existing laws and not by parliament.