But Mr Key rejected that.
"If we send him home to Tel Aviv, we don't have anyone we can register concerns with."
The Government had called in Mr Livne at least once in the past fortnight to raise concerns. It had also supported a motion in the House on the bombing of a school in Gaza last week, and UN Security Council resolutions on Gaza.
"Even Labour don't support sending the Israeli Ambassador home. The question is - what more could we do? We are strongly voicing our distaste," Mr Key said.
More than 1800 people have reportedly been killed in the conflict in Gaza, most of them Palestinians, including about 400 children. In the past month, at least 64 Israeli soldiers and three civilians in Israel have also been killed.
Mr Key said he was "horrified" by the violence, but stopped short of condemning Israel.
"I can point fingers, but I think it's better to urge dialogue. Tragically for the Palestinians, most of those people are refugees and they don't have a place to go."
Green Party global affairs spokesman Kennedy Graham said expelling the ambassador would send a clear diplomatic signal.
"Israel's refusal to heed the call of world leaders to stop the civilian slaughter in Gaza beggars belief."
He said 2013 figures from the New Zealand Super Fund showed $7 million of investments in 38 Israeli companies.
"New Zealand cannot sit by and take no action as more innocent Palestinians are killed. The Government must call on the Superfund to divest from these investments immediately.
"New Zealand should cut off ties at ambassadorial level until Israel's actions accord, once more, with proper international standards."