Israel's supreme court on Sunday disqualified the controversial leader of the extreme-right Jewish Power party, Michael Ben-Ari, from running in next month's elections.
Ben-Ari has come under fire for comments he made about Israeli Arabs, which Attorney General Avichai Mandelblit said earlier this month amount to "incitement to racism".
The elections committee had approved Ben-Ari to run in the April polls, but the opposition left-wing Meretz party successfully appealed the decision to the supreme court.
"The place of people who believe in the superiority of race is behind bars not in parliament," said Meretz leader Tamar Zandberg in a statement.
The attorney general previously accused Ben-Ari of "inciting on an ethnic-nationalistic basis against the Arab population" and "calling for a violent renunciation of the Arab population's rights."
According to Jewish Power, his disqualification marks the first time a candidate approved by the committee has been banned from standing in elections.
In a press conference following the ruling, Ben Ari said "a judicial junta is trying to impose its laws... it's not democracy."
Jewish Power are followers of late racist rabbi Meir Kahane, whose Kach movement was labelled a terrorist organisation by Israel, the United States and the European Union.
Prime Minister Benjamin Netanyahu, who is seen as leading the most right-wing government in Israel's history, brokered a deal to see Jewish Power join with two far-right parties to create a single electoral list.
The supreme court on Sunday approved Jewish Power's second candidate, Itamar Ben-Gvir, to stand in polls.
It also backed a candidate from the extreme-left Hadash party, Ofer Kassif, and approved the two main Arab alliances -- Hadash-Taal and Raam-Balad.
The latter had initially been barred by the elections committee over its alleged support for violent resistance.
A Raam-Balad spokeswoman welcomed the move, describing the committee's earlier ban as "a political decision".
"A decision that once more did not get beyond the supreme court, a decision based purely on the public's fear of the party's ideological platform," she said.
Raam-Balad is fiercely critical of Israeli policies, particularly the occupation of Palestinian territory.
Justice Minister Ayelet Shaked, a far-right politician and ardent supporter of Israeli settlements in the occupied West Bank, slammed the supreme court rulings.
"Disqualifying Ben-Ari and approving the parties which support terrorism is a flagrant intervention against the heart of Israeli democracy," she said.