Labor leader Bill Shorten has blamed Malcolm Turnbull's "arrogance" and poor judgment for the state of the Australian parliament.
Soon after arriving in Israel on Sunday (Monday AEDT), Mr Shorten vowed not to get into a debate about domestic politics while overseas.
But he couldn't help but lay into the prime minister for the "turmoil and chaos" caused by Barnaby Joyce's exit from parliament because of his citizenship status.
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He said the situation, including the by-election now facing voters in the northern NSW seat of New England, could have been avoided if Mr Joyce had stood aside until the High Court made its decision on the so-called "citizenship seven".
"Mr Turnbull's too arrogant for that and because of his arrogance and his poor judgment, we've now got the current turmoil," Mr Shorten told reporters in Jerusalem on Sunday night.
Labor has indicated it will challenge decisions made by Mr Joyce and Nationals deputy Fiona Nash, who was also found to be invalidly elected.
Fairfax reported the Opposition has sought legal advice and been told more than 100 decisions made by the pair could be challenged under section 64 of the constitution.
The Attorney-General George Brandis conceded the government was looking "very carefully" at whether any of its legislation is under threat but dismissed Labor's threats.
"I think you will find that there is no legal consequences here at all," Senator Brandis told Sky News on Sunday.
"Most decisions that ministers make are in fact made by the Cabinet on the recommendation of ministers."
The opposition leader will visit a refugee camp in Bethlehem and meet Palestinian Prime Minister Rami Hamdallah on Monday.
He'll also meet with representatives of the Israeli government and new leader of the Israeli Labor Party Avi Gabbay ahead of Tuesday's commemorative events marking the 100th anniversary of the charge of the Australian light horse brigade in Beersheba.
Mr Shorten reiterated his support for a two-state solution amid pushes by some grassroots Labor members to recognise Palestine as a state.
"I think the right of Israel is to live within secure borders and I also support the legitimate aspirations the Palestinian people to have their own homeland," he said.
"I'm here to hear how they think they're going, to hear their point of view."
