The Taoiseach has asked all Government departments and agencies to develop contingency plans in response to what he said is an escalating crisis which will have an impact on global stability, economies and inflation.
Micheál Martin said the situation developing in Ukraine shows no sign of abating and a severe escalation will have devastating consequences.
"We are seeing mass militarisation and we have seen nothing like this since World War Two," he said in comments to the Fianna Fáil parliamentary party.
Covid has been a tough two years for everybody, he said but this crisis will have an impact on global stability, economics and also inflation: "There will be a difficult period ahead," he warned.
Speaking ahead of attending an emergency EU summit, Mr Martin said sanctions "will impact everyone across the EU in different ways but are a necessary response".
"We have asked all departments and agencies to develop contingency plans in response to this crisis," he said.
The Government will show a "humanitarian approach" to the impact that this will have on migration, he said.
He added that there will be a cyber security risk that will be monitored.
Yesterday Mr Martin said a strong message needed to be sent to show Ireland's support of Ukraine.
Speaking during Leaders' Questions in the Dáil, he said that "we have witnessed a major escalation" in terms of Russia's decision to recognise breakaway regions.
He said Ireland would be part of an EU-wide sanctions regime, which has imposed measures on 27 individual oligarchs, business leaders, 351 members of the Duma, politicians, military leaders, Russian entities as well as imports and exports into the Donbass region.
Ukraine crisis is a 'dark moment'
Asked about Russian companies using the IFSC in Dublin, the Taoiseach said the sanctions would include the ability of Russia to use capital and financial markets in the EU.
He added the crisis was a "dark moment" and "it is very serious".
Mr Martin said "the sheer scale of the militarisation on the border of Ukraine is something we thought was a relic of the past" and the developments "had a chilling impact on small states".
He said Russia's security concerns can be addressed, but there is no need for this level of militarisation.
"This isn't a clash of two alliances at all, this is the aggression of Russia," Mr Martin said.
"There is no need for this incredible militarisation that NATO has had no hand, act or part in."
On the speech by Russian President Vladimir Putin this week, the Taoiseach said that "the most troubling aspect has been that speech and the context of that speech is that it brings us back to a different era in a different century."
He was responding to Labour leader Alan Kelly who warned that a full blown war was edging closer.
Deputy Kelly called on the Government to condemn Russia's actions and bring forward a motion on the matter and called on the Government to ensure Russian money flowing through Ireland will be targeted.
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Mr Kelly also called for Ireland to seek a derogation from the EU which would allow Ireland to reduce VAT on energy prices following concerns the crisis in Ukraine will add to fuel costs.
The comments come as political pressure has continued on the Government on rising energy prices.
Additional reporting David Murphy
