Arab League assistant secretary general Mohammed Sobeih urged Israel's Arab minority to go out and vote in today's parliamentary elections.
Mr Sabieh warned that the election could be dominated by the extremist right that openly supports forcing Arab Israelis to leave.
Mr Sobeih said his call was motivated by fears that under-representation of Israeli Arabs - about 20 per cent of the population - would allow the Knesset to adopt "racist" legislation but still look democratic.
Polls suggest that hard-line parties that have been the traditional allies of front-runner Benjamin Netanyahu will form the core of his next coalition government.
Up to one-sixth of the incoming legislature is expected to be made up of settlers who advocate holding onto all captured Palestinian land.
The extremist Jewish Home party is even pressing to annex large chunks of the West Bank, the core of any future Palestinian state.