Jacinda Ardern said that "New Zealand calls on Russia to do what is right and immediately cease military operations in Ukraine and permanently withdraw to avoid a catastrophic and pointless loss of innocent life".
The Prime Minister addressed media on Friday in light of Russia's "illegal invasion of Ukraine" which was launched on Thursday afternoon.
"More than 80 strikes have been carried out against Ukrainian targets and Russian ground forces are advancing across the border," Ardern said, adding there was reports of attacks in a range of areas and fighting around airports and areas of importance.
"Invasions poses a significant threat to the region, and will trigger a humanitarian and refugee crisis."
She said an "unthinkable number of innocent lives could be lost".
"New Zealand calls on Russia to do what is right and immediately cease military operations in Ukraine and permanently withdraw to avoid a catastrophic and pointless loss of innocent life.
Expelling the Russian Ambassador "does sit amongst the suite of options that sits in front of every country"," Ardern said.
"It is on the table as a potential prospect, it is not a decision we have taken at this stage. We do have our own people in Russia, they're able to provide support to New Zealanders who are in-country.
She said it was not a decision to be taken lightly given "wider ramifications".
Ardern said Russia had displayed a flagrant disregard for international law.
"They now must face the consequences of those decisions."
"We stand resolute in our support for those who bear the brunt for Russia's decisions."
On Thursday, New Zealand put a travel ban on Russian Government officials associated with the invasion, suspended bilateral foreign ministry consultations with Russia, and stopped the export of goods to Russian military and security forces.
Ardern said the ban on military exports would be significant and show support to Ukraine.
Foreign Affairs Minister Nanaia Mahuta said Russia demonstrated a disregard for these efforts and they must now face the consequences of their decision to invade.
Ardern called it an "unprovoked and unnecessary attack by Russia".
"By choosing to pursue this entirely avoidable path, an unthinkable number of innocent lives could be lost because of Russia’s decision."
On fuel supply, Ardern said the majority of New Zealand’s fuel was sourced from Middle East and Asia.
Energy and Resources Minister Megan Woods then put out a statement saying “any resulting curtailment of Russian oil supply won’t affect New Zealand’s fuel supply”.
“New Zealand does not purchase any oil or oil products from Russia so would not be directly affected.”
Ardern said there would still be an impact of international supply “but there will also be strong economic impacts on Russia”.
New Zealand would keep the possibility open for humanitarian assistance.