Prime Minister Jacinda Ardern said her cabinet agreed to deploy up to 30 members of the New Zealand Defence Force (NZDF) to Britain to train Ukrainian forces in the use of L119 105mm howitzers.

"We have been clear throughout Russia's assault on Ukraine, that such a blatant attack on innocent lives and the sovereignty of another country is wrong," said Ardern.

"Our response has not only included the condemnation of Russia, but practical support for Ukraine."

New Zealand previously deployed a C130 Hercules aircraft and NZDF personnel to Europe to provide intelligence, transportation and logistics support to Ukraine.

Ardern said the decision -- a sensitive one for non-interventionist New Zealand -- came after a request for assistance was carefully studied.

"We'll take every request in that way, looking at our independent foreign policy but also the parameters of our engagement with our defence force which we're very careful about," she said.

The deployment will run until the end of July and Chief of Defence Force Air Marshal Kevin Short said his personnel expected about 230 Ukrainian soldiers to be trained.

He estimated about 30 crews would be trained, with each taking a week.