Eamon Ryan has urged people to stop buying 'imported coal, oil and gas' from Russia, as it is directly funding the illegal invasion of Ukraine.
Another awful evening in the likes of Kyiv, Mariupol and Lviv saw at least four people killed while thousands remain trapped in cities.
The Russians offered a grim ultimatum to Ukrainian officials in Mariupol, only to be rejected immediately.
On Monday morning, the Green Party leader offered his thoughts on the conflict.
He told Morning Ireland that he believed Irish people could offer support in many ways - but urged one in particular.
He said: "One of the best ways we can actually take on this Putin regime is to stop sending the hundreds of millions of euros we send every day for the imported coal, oil and gas that helps fund this war. We have the potential, in doing that, to help in the war situation and also in our own independence. (By doing that) it protects us from the reliance on those fossil fuels.
"We can change this whole environment of being reliant on Russia's economic strength."
Mr Ryan also confirmed that Ireland will support further sanctions being brought in against Putin and Russia "as part of a united European Union response."
At least four people have been killed in shelling overnight which hit houses and a shopping district in Kyiv's Podil district.
The Kyiv department of the Ukrainian state emergency service confirmed the casualties after the late attack on Sunday evening.
The city's mayor Vitali Klitschko said: "According to the information we have at the moment, several homes and one of the shopping centres [were hit]."
READ MORE: The first symptoms you will feel in the next 48 hours if you caught Covid this weekend as cases rise
READ MORE: Covid Ireland: How to differentiate spring 'allergies' from the virus amid latest case surge
