"Our training team has been requested to help train members of Ukraine's Armed Forces in the use of the weapon system until the end of July.
"We will continue to monitor the situation and will work in tandem with our partners to ensure that we continue to make a meaningful and effective contribution."
Ardern said this deployment was another way the country could support Ukraine and demonstrated the specific skills New Zealand had, as few armed forces could provide this training.
"This new support comes in addition to the extensive assistance we have already provided to Ukraine, which encompasses the military, humanitarian, legal, and other aspects of the conflict," she said.
While they would be doing it from outside the contested areas, the support would still be significant, Ardern said.
Chief of Defence Force Air Marshal Kevin Short said 230 Ukrainians would be trained and it would take about a week for each training session.
Minister of Defence Peeni Henare, said he was pleased New Zealand could offer the skills and experience of the Defence Force through this training, and was clear NZDF personnel would not be entering Ukraine.
"The Government is acting on a call for help with training, which will enable members of the Ukrainian Armed Forces to operate L119 light field guns as they continue to defend their country against attacks by Russian forces," Henare said.
"We are also providing approximately 40 gun sights to Ukraine, along with a small quantity of ammunition for training purposes.
"An advance party will deploy this week with the remainder of the artillery training team deploying as soon as practicable. The training for the Ukrainian Armed Forces is expected to begin next month."
In a statement, Foreign Affairs Minister, Nanaia Mahuta said New Zealand has condemned and continues to condemn, unequivocally, Russia's unprovoked and unjustified attack on Ukraine.
"We continue to work closely with a range of international partners in supporting Ukraine, including providing military support such as this, humanitarian assistance and supporting efforts to ensure accountability for human rights violations," Mahuta said.
The Government previously approved the deployment of a Royal New Zealand Air Force C-130H Hercules aircraft and NZDF personnel to the United Kingdom and Europe to provide intelligence, liaison, transportation and logistics support to the international community's efforts to support Ukraine's self-defence.
The NZDF's New Zealand-based open-source intelligence capability has also been utilised, and military equipment has been donated to Ukraine.
New Zealand has also donated approximately $15.7 million to purchase military equipment for Ukraine, and commercial satellite access for Ukrainian Defence Intelligence, and has rolled out sanctions targeting those associated with Russia's invasion.
On the walkout over the weekend at an international meeting with Russia present, Ardern said these were examples of where forums are continuing and Russia participates countries choose to send clear messages.
Asked about any precedent this may set, Ardern said New Zealand's view was to be "in the room".
If Russia was present it was important to send the message "our view".
On former defence minister Ron Mark's visit to Ukraine and criticism of New Zealand's actions, Ardern said she disagreed with Mark and being present on the ground would not "add anything".
Having politicians visit in the middle of the war did not add anything, as opposed to what was announced today, Ardern said.
Ardern's message on US trip, meeting Biden
On the trade mission to the US, Ardern said she would take the simple messages that New Zealand was open for business and recreation.
As the US opened up she wanted to make sure New Zealand was at the forefront of their minds. The US is New Zealand's third-largest market.
Asked about her potential meeting with US President Joe Biden, Ardern said there had been an intention to meet before she contracted Covid-19.
On the CPTPP, Ardern said New Zealand had been pushing it and would continue while the US had been pushing its own Indo-Pacific arrangements.
Asked about Aotearoa's high death rate compared to the US, Ardern said it was not comparing "apples with apples".
New Zealand's actual death rate was about half what was reported when taking into account deaths directly linked to Covid-19, Ardern said.
Ardern is set to meet with social media giant Twitter while in the US.
Asked if she expected to meet with billionaire Elon Musk, who is acquiring the platform, Ardern said the meeting would be "with people of leadership in the company".
On her Covid experience and travel plans ahead, Ardern said she felt okay and she had prioritised rest. But she understood for some their experience had been much different.
Relationship with Australia 'strong and enduring'
On her meetings with Australia PM-elect Anthony Albanese, Ardern said the last in-person encounter was in February.
Albanese had called Ardern on his way to meet supporters, and they then agreed to speak again the following day.
Ardern said the relationship with Australia was "strong and enduring". She said Albanese had already acknowledged friction between the countries on certain issues, which was helpful as they had been "problematic".
She expected a good exchange of ideas, including on climate change which is particularly of interest in the Pacific.
From a regional perspective, she expected a conversation about what was occurring.
Asked about the 501 issue, Ardern said her position had not changed.
While the Government "understood circumstances of people being deported" the area of grievance was those with little or no connection to New Zealand.
Ardern said she would not give anything away about her Harvard address. But she said she was "very humbled" by the opportunity, and had spent "quite a bit of time" thinking about what to say, on behalf of the country.
Russian sanctions
The Government has previously imposed five rounds of sanctions covering more than 700 Russian individuals and entities.
And in late March, nine New Zealand Defence Force personnel were deployed to the United Kingdom and Belgium to support other countries with tasks, including intelligence assessments.
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.
Russia pressed its offensive in eastern Ukraine on Sunday, AP reported.
And Polish president Andrzej Duda travelled to Kyiv to support Ukraine's European Union aspirations.
"I want to say clearly: Only Ukraine has the right to decide about its future. Only Ukraine has the right to decide for itself," Duda said.
Today's post-Cabinet press conference also follows Anthony Albanese and the Australian Labor Party's victory in the Australian Federal election.
Ardern has already congratulated Albanese, who emerged victorious over Scott Morrison after six weeks of campaigning, ending the conservative Coalition's almost decade-long reign.
National Party leader Christopher Luxon also congratulated Albanese, and said Australia was "New Zealand's closest friend".
