New Zealand is sending 30 Defence Force personnel to the UK to train members of the Ukrainian military in using a specific type of gun.
They will be stationed in the UK until the end of July. At no point will they go into Ukraine.
New Zealand was asked to help train the Ukrainian forces in using L119, 105mm Light Guns.
Prime Minister Jacinda Ardern said more than 230 Ukrainian forces would be trained by the NZDF. It will take at least a week for a gun crew to be trained.
"This additional deployment as really another way New Zealand can support Ukraine," she said.
"There are very few armed forced who can provide this training right now."
She said it could make a "significant difference".
The L119 is only used by a handful of countries, Ardern said.