In today's Focus on Politics podcast, Political Editor Jane Patterson examines the state of play in Ukraine, and the legal and political instruments being brought to bear against Russia.

"If Putin remains in power and he physically remains in Russia, there's not really anything that can be done. The only possibility would be a coup that overthrows him ... or if Putin travels outside of Russia" - Stephen Smith

Russia's invasion of Ukraine is bringing new images every day of destruction, and allegations of war crimes and crimes against humanity.

It brings calls for justice, for the prosecution of Russian president Vladimir Putin, and for reform at the United Nations.

New Zealand experts say it's possible, but prosecution and reform alike could take years.

Listen to the full podcast here

US President Joe Biden has outright called Putin a war criminal, and National's Christopher Luxon has said he'd be comfortable doing the same.

Most leaders are more circumspect however, including Prime Minister Jacinda Ardern who argues it's up to the International Criminal Court to make that determination.

It's a position that has the rare agreement of ACT leader David Seymour: "It's not up to a politician to decide if someone's guilty, it's up to a court, and I think Jacinda Ardern has got that one right. You won't hear me say that often."

Ardern, Luxon and Seymour alike - along with all other MPs, the intelligence agency chiefs and top defence officials - have been placed on Russia's travel blacklist, and it seems likely the tit-for-tat will only escalate.

Read more:

Russia's travel blacklist on 130 New Zealanders

Analysis: Justice may wait as evidence of Russia's crimes is gathered

'What did they liberate us from?': Russian troops' brutality detailed

Russia suspended from UN Human Rights Council

Mahuta tight-lipped on sending weapons to Ukraine

Putin's Ukraine war creating 'significant war crimes' - Mahuta

Luxon labels Putin a war criminal, again urges ambassador's removal

Internationally, Russia has already been suspended from the UN Human Rights Council over alleged atrocities, and Ukraine's president Volodymyr Zelensky has been urging its expulsion from the Security Council. As one of the five permanent members of the council Russia's veto guarantees it a diplomatic trump card.

New Zealand's former Security Council ambassador Colin Keating told Midday Report reform of the UN is possible, but it will take political will - and may take some time. …

Go to this episode on rnz.co.nz for more details