Alongside Sir Keir Starmer, Mr Luxon will visit New Zealand and British troops at a base in Wiltshire on Tuesday, where the combined forces are training thousands of Ukrainian soldiers for battle.
New Zealand, which has announced a multi-billion dollar uplift in defence spending, is mulling its commitment to the "coalition of the willing", announced by the UK in March.
Sir Keir has led the formation of a predominantly European grouping that stands ready to send troops to Ukraine in the event of a peace deal with aggressor Russia.
Mr Luxon said those were "ongoing discussions" that would be had with his counterpart.
"We clearly as a small country with limited resources a long long way away (from Ukraine) aren't going to be the ones that end that war," he told Newstalk ZB on Tuesday.
"That's for Europe, Ukraine, the US and Russia to work towards.
"Regardless, we stand very strongly with our values which we think Ukraine embodies and Zelenskiy embodies very, very strongly and it's important that we play our part and stand up for those values."
Mr Luxon added he thought Ukrainian President Volodymyr Zelenskiy was "a hero" and it was Russia that needed to "step up and progress ceasefire negotiations".
"The ball's in their court ... this is an illegal unprovoked aggression from Russia," he said.
One of NZ's most significant contribution to the conflict has been its stationing of up-to-100 troops in the UK to help train Ukrainian forces.
On the eve of his visit, Mr Luxon announced the extension of that force's mandate through to the end of 2026.
Vasyl Myroshnychenko, Ukraine's Ambassador to Australia and New Zealand, signalled his appreciation for the commitment on social media.
Sir Keir said NZ was a long-standing and much appreciated partner.
"From the beaches of Gallipoli, to the vital work we have been doing together on Operation Interflex and our support for Ukraine, the UK and New Zealand have stood shoulder-to-shoulder for generations in pursuit of peace and stability," he said.
The UK government has also announced it will spend $NZ67 million ($A63 million) on NZ-made drones produced by SYOS Aerospace.
On the first day of his visit to the UK, Mr Luxon met King Charles, and in line with royal convention, opted against giving details of the meeting.
"Suffice to stay he's always very interested in what's going on in New Zealand and he's pretty informed about what's going on in the world," he said.
Mr Luxon will conclude his visit to Europe by attending Anzac Day commemorations in Gallipoli.
"It's a pretty special place, as a kid growing up in New Zealand I've read a lot about it, being a history buff," he said.
"It's poignant this week to be here in the UK talking defence and the work we've been doing with the Brits and then thinking 110 years ago we were working with Brits as well in Gallipoli."
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