The outburst was not unusual for Israel's raucous parliament but Israeli pundits saw the violent nature of the argument as a sign of rising political tensions, spurred on by speculation that national elections may be held earlier than 2013.

Lawmaker Ghaleb Majadleh, an Israeli Arab member of the left-leaning Labour party, had protested at an education panel meeting against the reprimand of an Arab school principal for letting pupils attend a human rights group rally.

"You are inciting against the state," retorted Anastasia Michaeli, a member of Foreign Minister Avigdor Lieberman's rightwing Yisrael Beitenu (Israel Our Home) party.

When Majadleh told her to "shut up" Michaeli rose from her seat, poured water into a plastic cup and threw it at Majadleh, dousing his face and jacket, before heading for the door.

Michaeli told reporters Majadleh had been rude.

"If there are no men in the Israeli Knesset willing to defend women, then I will defend myself, the honour of my party and of the Knesset," Michaeli said.

Majadleh, a former cabinet minister and the only Israeli Arab citizen ever to hold such a position, accused Michaeli of staging a provocation and denied insulting her.

Michaeli's party scolded her, issuing a statement that she had been told "no circumstances could justify such behavior" but also accusing Majadleh of having provoked her outburst.

Speaker Reuven Rivlin said he would lodge a complaint with the house's ethics committee over Michaeli's action, which he called "an insult to the entire Knesset".

Israeli media said Michaeli could be suspended temporarily from her post. It was the second time she has faced censure. She was removed from a debate a year ago after trying to interrupt a speech by another Arab lawmaker, Haneen Zoabi.

Rivlin saw the incident as part of what he called "an atmosphere as though elections are soon to be held".

He foresaw the possibility of further "gimmicks and hijinks for which the Knesset and Israeli democracy are liable to pay the price".

Israel's next parliamentary election is scheduled to be held in 2013, but speculation has been rife that the date may be advanced since Prime Minister Benjamin Netanyahu's called a snap leadership vote later this month for his right-wing Likud party.