New Zealand sends aid not guns to Ukraine

Rather than sending financial support to the military - or lethal or non-lethal arms - New Zealand is focusing elsewhere.

"We've stepped into the humanitarian space because we see a gap and a need there," Ms Ardern said in Wellington on Wednesday.

New Zealand is also lagging other countries in the sanctions it places on Russia, as it is hamstrung by its own legislation which requires sign-off by the United Nations Security Council.

Given Russia has veto power on the UN body, New Zealand has been limited to implementing travel bans on the movement of Russian government officials.

Ms Ardern said she was working on a bespoke piece of legislation that would enable New Zealand to join the international sanctions effort.

"My expectation is we'll have something ready to go next week. We will also talk to other political parties about support for their package as well," she said.

"This will very much focus on the gaps that exist through the potential movement of assets and investment out of Russia."

Ms Ardern said the expulsion of the Russian ambassador in Wellington remained "on the table".