New Zealand will send 30 troops to Britain to train Ukrainian forces how to use a type of howitzer.
Prime Minister Jacinda Ardern today said the Defence Force personnel would stay in the UK until the end of July for L119 light gun training.
The 105 mm calibre gun can be used in either offensive or defensive operations, according to the NZDF.
Ardern said New Zealand had been asked to help teach Ukrainians to use the guns, and Defence Force personnel would remain in the UK throughout the training.
Chief of Defence Force Air Marshal Kevin Short said 230 Ukrainians would be trained and each training session would take about one week.
Ardern said no further training request had been made.
The PM said the new deployment was another way New Zealand could support Ukraine.
The New Zealand Army said vehicles usually towed L119s into position but the guns could also be carried as a sling load underneath a helicopter for faster deployment.
The system included wheels, suspension, a recoil system, saddle and elevating gearbox, according to manufacturer BAE Systems.
"Normal manning for the light gun is with a crew of six but it can be adequately operated by a crew of just three," a BAE brochure added.
The ordnance comprised a one-piece, forged barrel of 30 calibre (3.2m) length and a manually-operated breech.
Former Defence Minister Ron Mark has visited Ukraine, and for weeks has been arguing New Zealand do more to help the country after Russia's invasion.
Ardern said she was fond of Mark but disagreed with some of his recent comments and believed him being on the ground would not "add anything".
The howitzer training was more useful than having politicians visit in the middle of a war, she said.
The National Party supported the contribution and Cabinet decision announced today.
Sending troops to train Ukrainian soldiers was appropriate, and continued New Zealand's proportionate response to Russia's invasion, foreign affairs spokesman Gerry Brownlee said.
"The Government should be clear in signalling what next steps it is considering as part of New Zealand's ongoing response," he added.
The party's defence spokesman Tim van de Molen said the NZDF personnel and their expertise would help Ukraine's effort to defend against Russia's atrocities.
"It's important that New Zealand remains in step with our traditional partners in defence of our values," he added.
The Government has previously imposed five rounds of sanctions covering more than 700 individuals and entities connected to the Russian and Belarusian regimes.
New Zealand also previously approved deployment of a Royal New Zealand Air Force C-130H Hercules aircraft and NZDF personnel to the United Kingdom and Europe.
The aircraft were supposed to provide intelligence, liaison, transportation and logistics support to the international community's efforts to support Ukraine's self-defence.
In late March, nine New Zealand Defence Force personnel were deployed to the UK and Belgium to support other countries with tasks including intelligence assessments.
The NZDF's open-source intelligence capability has also been used, and military equipment donated to Ukraine.
New Zealand has also invested about approximately $15.7 million to purchase military equipment for Ukraine, and commercial satellite access for Ukrainian Defence Intelligence.
New Zealand has also called for accountability for alleged Russian war crimes.
Vasyl Myroshnychenko, Ukraine's Ambassador to New Zealand, urged the Government two weeks ago to do more to support his country in its war with Russia.