"If they want the government to fall, let it fall," he told Israeli Army Radio.

The 120-member Knesset is voting on an opposition move to bring elections forward to early 1999 from late 2000.

The BBC's Lyse Doucet: This is one of the most serious threats to Mr Netanyahu's rule

If Mr Netanyahu's opponents gather more than 60 dissident deputies to support early elections, the government will fall.

The vote is one of the biggest challenges to face Mr Netanyahu since Israelis elected him in May 1996 on a promise to pursue peace with security.

The vote comes amid fresh violence

Mr Netanyahu said: "I don't know whether I have 61 members of the Knesset. That we'll see. But I have a few solid principles and I am standing on them and on them I am ready to be tested by the public.

"I am also prepared to withstand the risk of a collapse of the government. If someone wants to threaten or topple me, let him try. I am not prepared to give up on these things.''

The vote comes amid fresh West Bank violence and just days ahead of a visit by President Bill Clinton.

Mr Clinton's trip is intended to solidify the Middle East interim peace deal agreed in October which has caused deep divisions in Mr Netanyahu's government.

Some members believe early elections may be the best way to stop the peace process which includes the further withdrawal of Israeli troops from 13% of the West Bank.

Labour ditches support

Despite opposition from coalition partners, Mr Netanyahu has remained in power with the help of the opposition Labour party which wants to see the accord carried out.

But he angered Labour last week when his cabinet suspended peace moves with the Palestinians.

Our Jerusalem Correspondent Lyse Doucet says some politicians are clearly trying to find ways to spoil the atmosphere in the run-up to Mr Clinton's visit.

Last month, Mr Netanyahu survived a budget vote but only after Arab deputies and the Labour opposition gave their support.