New Zealand will impose more sanctions on Russia tonight after reports of Ukrainian civilians being abused, murdered and buried in mass graves. 

"Russia must answer to the world for what they've done," Prime Minister Jacinda Ardern said this afternoon. 

The letter V, the Russian forces emblem, is seen on a blown Russian tank turret in the village of Dmytrivka close to Kyiv, Ukraine, on Saturday. Photo / AP 

The PM said Cabinet considered more steps to help Ukraine, and Russia must be held accountable for atrocities that were "beyond reprehensible". 

New sanctions targeting oligarchs with close ties to Vladimir Putin or his regime will take effect at midnight. 

Foreign Minister Nanaia Mahuta said the Government approved new sanctions on 36 people, all oligarchs or close relatives of those oligarchs. 

"This list includes some of Russia's richest businesspeople, as well as chairs and chief executives of some of Russia's biggest companies," Mahuta said this evening. 

"They will not be able to travel to Aotearoa New Zealand, move assets here, or use our financial systems to hide from sanctions imposed by other countries." 

Last month, more than 100 people including President Vladimir Putin and corporate executives were banned from travelling to New Zealand after the invasion of Ukraine. 

Prime Minister Jacinda Ardern said Russia must be held accountable for atrocities which were "beyond reprehensible". Photo / Mark Mitchell 

Ukraine has accused Russian troops of war crimes after mass graves and civilian executions were investigated in Bucha, close to the capital Kyiv. 

Ardern at the post-Cabinet press conference was asked if she would call Vladimir Putin a war criminal. 

She several times said the evidence indicated Putin's regime was committing war crimes. 

But she added: "Ultimately it is for the International Criminal Court to make that determination." 

Ardern said she was not an ICC judge, so it was not her place to affix the "war criminal" label. 

The PM said very few countries had recalled diplomats from Russia. 

Instead, many countries had already applied sanctions, tariffs and travel bans to Russia, and military aid and equipment to Ukraine. 

She said diplomatic expulsions were an option but the Government had prioritised "more impactful options" for now. 

Ukrainian President Volodymyr Zelenskyy speaks from the capital, Kyiv. Photo / Ukrainian Presidential Press Office 

Ardern said some of those other options related to sanctions and imports. 

Asked if New Zealand would send lethal military aid, she said there was sometimes an artificial distinction around the "lethal aid" term. 

She said the key question was: "What's the biggest and most important contribution New Zealand can make?" 

- by John Weekes, NZ Herald