Luxon challenged her to name tools the Government could use to trim inflation - essentially goading Ardern to promise to cut spending.
Luxon singled out the Government's decision to spend "billions on vanity projects like underground trams" as a particularly egregious funding choice.
Ardern challenged Luxon to list what he would choose to cut, if he wanted to slash spending to contain inflation but Speaker Trevor Mallard ruled that tactic out of order, noting questions were for the opposition to ask the Government, and not the other way around.
Earlier, Ardern blasted her Russian counterpart Vladimir Putin over his country's "brutal and intolerable act of aggression" as she put forth a motion to condemn the invasion of Ukraine.
"New Zealand and international partners call on Russia to do what is right and call for an immediate end to military operations and permanent end to a pointless war."
She concluded with: "Slava Ukraini" - or "Glory to Ukraine".
Leaders of each political party supported the motion, and spoke out against the threat to the international order and looming humanitarian crisis.
Russian forces are closing in on the Ukrainian capital of Kyiv. There have already been hundreds of casualties, and up to four million displaced Ukrainians are expected to cross borders in the coming days and weeks.
The United Nations believes more than 500,000 people have already fled.
New Zealand has committed an initial $2 million to help deliver essential humanitarian aid, banned high-ranking Russian individuals from travelling and prohibited exports linked to the Russian military.
Ardern said New Zealand was pursuing further actions including targeting Russian investments here.
Luxon said the invasion was an "affront to human rights, democracy and global peace and stability".
He said it was "heartbreaking" to see Ukrainians just days ago going about their normal lives and now having to "fight for their country".
The National Party has urged stronger action on the Russian invasion, including expelling the Russian ambassador and introducing an autonomous sanctions regime.
Luxon also repeated calls from his party to welcome Ukrainians fleeing the Russian invasion, and create special humanitarian visas.
New Zealand's economic sanctions are guided by UN resolutions, making them near impossible as Russia has a veto on any resolutions in the United Nations Security Council as a permanent member.
Australia has enacted a range of sanctions on Russia but so far held off expelling diplomats.
Act Party leader David Seymour urged the Government to pass legislation allowing such sanctions under urgency.
"If ever there was a time to use urgency in passing that legislation the time is right now, so we can join that moral movement against Vladimir Putin."
Seymour praised the "grit and courage from ordinary people" in Ukraine, defending their homes and urged the Government to take stronger actions.
"No country has more to lose than New Zealand when rules-based, values-based international order is lost and thuggery takes its place."
Green Party co-leader James Shaw said watching the full-scale attack on the people of Ukraine was "frightening and depressing".
The party "strongly condemns the extraordinary violence", he said, and also strongly supported humanitarian aid efforts and urged the Government to take in refugees.
"A world without war is possible but does require enduring commitments by all nations to peace-building and diplomacy."
Te Pāti Māori co-leader Rawiri Waititi began with a mihi in te reo Māori and acknowledged those who had died.
"Our hearts go out to the people of Ukraine whose world was shattered overnight.
"When rich and powerful play war games it is the people who pay the price."
Waititi said working people had been caught in the "proxy war" fought by imperialists.
Māori knew the impacts of such conflict only too well, he said.
"Te Pāti Māori wholeheartedly condemn the actions of Putin and his government."
National's immigration spokeswoman Erica Stanford earlier called for the Government to create a "special humanitarian visa" for immediate family members of Ukrainians who have settled in New Zealand.
Stanford said the Government should also be fast-tracking existing visa applications for Ukrainians, as Australia has done.
The Greens want the Government to urgently offer to resettle refugees
New Zealand resettles a maximum of 2000 refugees a year, through the United Nations High Commissioner for Refugees (UNHCR) regular refugee resettlement programme.
Greens foreign affairs spokeswoman Golriz Ghahraman said the Government's response must "focus first and foremost on what we can do to support ordinary people facing crisis".
She said the Government should offer places to 2000 refugees, given the national quota had not been filled for two years because of Covid.
Ukraine's representative, Sergiy Kyslytsya, told the UN this morning: "Do not listen to Russia's lies, listen to Ukraine's cries. We need your help."
The plea came during an emergency meeting of the UN's Security Council in which the scale of the humanitarian crisis was revealed, and as claims emerge that Russia has dropped a devastating bomb on Ukrainian territory.
Kyslytsya spoke out on the last day of Russia's tenure as President of the security council in a meeting when member states claimed that Russia was using illegal cluster munitions.
Russia's representative, Vasily Nebenzya, said that the Ukrainian people were being held hostage by "radicals" and claimed that civilians were being protected in areas now held by Russia.
He claimed that "dirty lies" were being spread by Ukraine and amplified by Western media, telling the council that Ukraine was placing forces in civilian areas and Russia was not targeting civilians.
Kyslytsya said the invasion "violates the conscience of the world".
Speaking at the UN overnight, Foreign Affairs Minister Nanaia Mahuta told the world New Zealand strongly condemns Russia's invasion of Ukraine, saying it is the "act of a bully" and "must stop".
Mahuta, in her speech to the United Nations Human Rights Council, said the Russian Government had repeatedly ignored opportunities for diplomacy, negotiation and de-escalation and had instead chosen aggression.
Mahuta warned Russia's actions would have far-reaching and serious humanitarian, security and economic implications for Ukraine, Russia, Europe, as well as the rest of the world.
"This is a clear act of aggression; a blatant breach of Ukraine's sovereignty and territorial integrity; and a violation of international law and the UN Charter by a Permanent Member of the Security Council," she said.
"We are witnessing the blatant act of a bully, brutally using its unbridled power to achieve goals at odds with international law. Sadly, women and children are already the innocent victims of this illegal aggression. This cannot be tolerated."
Mahuta repeated New Zealand's calls for Russia to act consistently with its international obligations, cease military operations in Ukraine, permanently withdraw its troops, take all possible steps to protect civilians in line with international humanitarian law, and return to diplomatic negotiations as a pathway to resolve this conflict.
"We must not let diplomacy fail, we must persevere in the pursuit of an outcome that prevents further suffering. War, Mr President, must stop."
- additional reporting by Thomas Coughlan
