The "Coalition of the Willing" phone call was arranged by British Prime Minister Sir Keir Starmer, and was attended by, among others, Ukrainian President Volodymyr Zelenskiy, French President Emmanuel Macron and Australian Prime Minister Anthony Albanese.
Other nations included Germany, Italy and Canada and NATO's secretary general - but not the United States.
"New Zealand stands shoulder to shoulder with Ukraine," Luxon wrote on X after the call last night.
"Our discussion included how to support Ukraine to achieve a just and lasting peace."
A New Zealand defence attaché had already been participating in talks in Paris, along with officials from about 30 countries.
New Zealand was originally not expected to participate in the call, but on Friday, Luxon confirmed he had been invited and accepted.
"It will be a chance, really, for an update as to the different lines of diplomatic efforts that are going in across securing peace in Ukraine," he said at the time.
'Coalition of the willing'
Starmer said on Saturday that Western allies were stepping up preparations to support Ukraine in the event of a ceasefire with Russia, with defence chiefs set to firm up "robust plans" next week, Reuters reports.
The British PM hosted the virtual meeting to marshal more pressure on Russian President Vladimir Putin to accept a ceasefire deal being pushed by US President Donald Trump, and to gather commitments to help secure any agreement - something Trump has made clear he expects Europe to take on.
Starmer said the "coalition of the willing" had reaffirmed its commitment both to helping Ukraine resist Russia's three-year-old invasion and to securing any ceasefire that emerges from Trump's overtures to Russia.
While Russia has welcomed the ceasefire proposal in principle, it has also set conditions that essentially restate its war aims, suggesting that any agreement will not come quickly.
Starmer told reporters: "We agreed we will keep increasing the pressure on Russia, keep the military aid flowing to Ukraine, and keep tightening restrictions on Russia's economy to weaken Putin's war machine and bring him to the table."
Britain and France say they could send peacekeepers to Ukraine in the event of a ceasefire. Australian Prime Minister Anthony Albanese said his country was also open to requests.
Even if a truce is agreed, though, much remains unclear, including the details of the US position.
Zelenskiy said he had underlined Ukraine's need for security guarantees, including the stationing of foreign troops.
Yet Russia insists it will not accept Western forces on Ukrainian soil.
And Starmer has said that, to deter Putin from attacking again, there must be a security "backstop" from a reluctant Washington, whose forces, weaponry and logistics are the backbone of the Western NATO alliance.
"We are talking to the US on a daily basis," he said.
- additional reporting by Reuters
