Tánaiste and Minister for Foreign Affairs Simon Harris will bring a proposal to Cabinet on Tuesday providing an additional €100 million in financial assistance for Ukraine.
Speaking to RTÉ's This Week programme, Mr Harris said the funds would be used for non-lethal military support, such as military vehicles and demining.
"That will basically involve providing money that will be used to purchase things like armoured vehicles, that can assist in demining and cyber protection measures, non-lethal use of military equipment," he said.
"Separate but linked to that will be the European Council meeting later in the week where the European Union will decide a package of support that it wishes to put in place, and Ireland will obviously have to contribute to that as well.
"Whatever the cost is, the cost of not paying it is much more significant in terms of the security of the European Union, in terms of the defence of a sovereign country, the largest country on the continent of Europe.
"This is a time to be on the right side of history and to actually stand up for the UN charter, stand up for freedom, stand up for a country's sovereignty."
The Tánaiste said Ireland would give 2% of what ever total is agreed at that meeting - meaning that if €2 billion was signed off by EU leaders, then Ireland would contribute €400 million.
He also said a "gulf" now exists between the European Union and the United States on the issue of Ukraine.
He said evidence of that chasm was seen at the United Nations last week, when the US voted with Russia, North Korea and Belarus against a UN motion on Ukraine.
However, Mr Harris added that Europe was responding by "bringing together people who share a common view".
He said he had a "deep sense of being unsettled" following a clash at the White House this week between Ukrainian President Volodymyr Zelensky and Mr Trump.
"There is only one aggressor here and the aggressor's name is Putin," the Tánaiste said.
"There aren't two equal people and I don't like any attempt to portray what is happening to Ukraine as some sort of squabble between neighbours.
"There is a country that was living peacefully in Europe that has been brutally and illegally invaded by Russia.
"Ireland will stand with Ukraine, so will Europe, and this week at Cabinet I will bring specific proposals to provide more financial assistance from Ireland to Ukraine in a practical way.
"It is fair to say a gulf has emerged between the United States and European Union in terms of this issue.
"That wasn't just seen in the Oval Office last week, though that was a very tangible way of seeing it, it was also seen at the UN General Assembly where the United States of America voted with Belarus, Russia and North Korea and not with their European allies.
"I think that does give you a sign of the gulf in terms of approach that has developed.
"But what is within the control of the European Union and Ireland is providing practical assistance to Ukraine.
"What we are seeing in our nearest neighbour the United Kingdom today is a practical way of bringing together nations who share a view."
UK Prime Minister Sir Keir Starmer is hosting a number of European leaders in London to discuss the situation in Ukraine.
Asked if he would support an invitation being given to President Trump to visit Ireland, the Tánaiste replied that he would have "no difficulty" with that should it arise.
The correct political approach was to focus on being constructive, he added.
Additional reporting by PA
