The attacks included a wave of rockets being launched into Israel by Hamas, and fighters entering Israel killing people and taking hostages.
Israel has reported about 250 people dead and hundreds injured as a result, and launched attacks of its own with officials saying at least 230 Gazans had been killed, according to Reuters.
New Zealand's Prime Minister Chris Hipkins on Sunday afternoon told reporters New Zealand "condemns unequivocally the Hamas attacks on Israel, we are appalled by the targeting of civilians and the taking of hostages which violate fundamental international humanitarian principles".
"New Zealand's designated the military wing of Hamas as a terrorist organisation, we recognise Israel's right to defend itself, we are concerned that the situation will escalate in the coming days and New Zealand again calls for restraint, the protection of non-combatants, and the upholding of international humanitarian law by all parties."
He said 87 New Zealanders were registered on the safe travel website as being in Israel, and one registered in the Occupied Palestinian Territories, and consular support was available to any New Zealanders in that part of the world who were concerned about their safety on +64 99 20 20 20.
New Zealand has for some time had "do not travel" advice for both Israel and the Palestinian territories, and Hipkins said that was a "fairly serious expression of New Zealand's concern" - and those New Zealanders still there were best placed to make decisions about their own safety.
"Aotearoa New Zealand is deeply concerned at the outbreak of conflict between Israel and Gaza," she said. "We call for the immediate cessation of violence. The protection of all civilians, and upholding of international humanitarian law is essential."
She posted a second message more than seven hours later, saying New Zealand "utterly condemns the terrorist attacks led by Hamas on Israel, and continues to urge restraint from all parties in the region in order to prevent the further loss of civilian lives".
With one week left in the election campaign, National's Christopher Luxon said it did not look like the two were "on the same page".
"I don't know what that relationship between Chris Hipkins and Nanaia Mahuta looks like, it doesn't look like they're on the same page," he said.
"We made our statement very clearly and I appreciate Chris Hipkins has followed that after us, but I just say to you again it's another example of a government falling apart."
Luxon's statement was a tweet at 10am, saying he was "shocked and saddened by the attacks overnight against Israel. We condemn these Hamas attacks on Israel and the violence and suffering being inflicted on innocent civilians. There is no justification for these attacks and Israel has a right to defend itself."
ACT leader David Seymour soon after released a statement criticising Mahuta for failing to "condemn" the attacks. Speaking to reporters in the afternoon, he said it was "absolutely disgraceful" for her to use the softer language of concern, "as though it is some sort of random occurrence".
"This is a brutal invasion on a democratic country that involves mass violence against civilians," he said. "It is critical that New Zealand's government stands with our allies and our country's values and unequivocally condemns this invasion and the ACT party unequivocally condemns this invasion by Hamas.
"The attacks on innocent civilians must stop and New Zealand needs to stand up and be counted on a question of values such as this Hamas invasion of Israel."
He said New Zealand should be standing with its Five Eyes partners on the matter.
Hipkins however said it was a matter of timing, "in terms of when we got the information through about the scale of what was happening there, so this is my first opportunity to issue a formal statement on it".
"From time to time a response will evolve as more information comes to light ... what the world should be reassured by is that New Zealand absolutely condemns these attacks.
"I wasn't involved in the discussions earlier this morning but I have been, obviously, since then. And hence I've made the statement now ... we absolutely condemn those attacks and we absolutely respect Israel's right to defend itself as well."
Green Party Foreign Affairs spokesperson Golriz Ghahraman called both on Palestinian armed groups and Israeli security forces to "make every effort to protect the lives of civilians in today's outbreak of fighting in Israel and the Occupied Palestinian Territories."
Asked whether the party condemns the Hamas attack, she said:
"Violence against civilians, whether committed by Hamas or the Israeli Defence Force is utterly unacceptable. The path forward from the latest bout of violence must be lasting peace, supported by the international community."
In her own earlier tweet, she drew attention to an article by an Israeli journalist highlighting the plight of Palestinian residents after decades under a conservative Israeli regime which routinely carries out raids.
New Zealand is one of 55 countries in the 193-state United Nations that does not recognise Palestine as a state. However, the government in the past couple of weeks said it would consider meeting with the Palestinian ambassador to assess his credentials - a first step in the process towards diplomatic relations.
Hipkins said the increase in hostilities would not affect those plans.
"No, not necessarily. But Hamas is recognised by New Zealand as a terrorist organisation and the plan to invite the Palestinian ambassador to present their credentials was not going to change that."
"I do, but I also think we've got to be realistic about what New Zealand's contribution is here," Seymour said. "We should be expressing the right values first and foremost. Israel has a right to exist, and it has a right to defend itself against this kind of incursion.
"Israel's not perfect either. They've had some real upheavals and internal difficulties this year too but nobody deserves what is happening to those people right now.
"I've always thought that the Palestinian people are to a large extent victims of Hamas just like the Israeli people are right now. I mean it's very clear that this is a terrorist organisation, I just wish that New Zealand had a government that was prepared to say that."
Luxon said he wanted to maintain New Zealand's long-standing position, "which is that through diplomacy and peace we want to see a two-state solution emerge. That's our long-standing position, it maintains our position".
Asked if National would invite the Palestine ambassador to present their credentials, he said that was "not our position".
By Russell Palmer
