An ultranationalist Israeli parliament member faced possible suspension from the Knesset on Monday for hurling a cup of water at an Arab colleague when he told her to "shut up" during exchanges over school students attending human rights rally.

Ghaleb Majadleh, an Israeli Arab member of the Labour party, had protested at an education panel meeting to reprimand 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 the 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, hitting his face and jacket, before heading for the door.

The outburst was not unusual for Israel's raucous parliament but many see 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.

Michaeli later 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," she said.

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

Michaeli's party scolded her, issuing a statement that she had been told "no circumstances could justify such behaviour", but also accused Majadleh of provoking 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. This is the second time she faces censure. She was removed from a debate a year ago after trying to interrupt a speech by another Arab parliamentarian, Haneen Zoabi.

Rivlin said the incident was part of "an atmosphere as though elections are soon to be held". He said there was possibility of further "gimmicks and hijinks for which the Knesset and Israeli democracy are likely to pay the price."

Israel's next parliamentary election is scheduled to be held in 2013, but speculation has been rife that it may be brought forward, following prime minister Binyamin Netanyahu's call for a snap leadership vote of Likud party later this month.