The Taoiseach has described the Brexit process as "traumatic" but said it has "not proven fatal" to the European family.
Speaking in Bavaria, Leo Varadkar said the Peace Process was born out of the European ideal and it cannot be allowed to falter.
At a speech to a conference of the CSU party in Bavaria - a sister party of Germany's CDU - he reiterated his determination to prevent the re-emergence of a hard border of the island of Ireland.
He said: "Despite the ever-shifting sands on the trek towards a settled Brexit destination, two things have stayed constant. The first is European support for Irish concerns and safeguarding peace on our island."
He added: "The second is our understanding of what must be defended. We are determined to protect the Good Friday Agreement: peace in Britain and Ireland; power-sharing in Northern Ireland, and ever closer co-operation North and South."
He said he hopes the future relationship between the EU and Britain after it leaves can be "as close, comprehensive and ambitious as possible."
In a wide-ranging speech, the Taoiseach called for a new system of voting for the European Parliament elections.
This would involve the introduction of pan-EU lists of candidates for seats - an idea already being pursued by the French President, Emmanuel Macron.
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"Let's get people in the beer halls of Bavaria and the cafes in Cork talking about the same election choices," he said.
He said Ireland has moved from being a net beneficiary of the EU budget to being a net contributor, and is open to spending more, "but only if it spent on things that contribute to the advancement of the European ideal."
The European Parliament elections, taking place in May, "will determine the future shape of the EU for the next decade," he said.
Addressing delegates who are members of the same EU Parliament grouping as Fine Gael, the European People's Party, he said: "Populists of the left and right condemn us and seek to divide our societies and our continent. They will not succeed."
The Taoiseach also called for more "burden-sharing" of the migrant crisis, saying "a small number of countries are shouldering the responsibility of providing refugees with a fresh start in Europe."
He said that leaders also need to be "mindful and respectful of the concerns of our own populations, particularly in this time of disinformation, confronted by the consequences actual and alleged of unplanned large-scale migration."
Speaking to the media before his address, Mr Varadkar said the Government is intensifying preparations for the possibility that Britain crashes out of the European Union without an exit deal, even though it expects agreement in the coming weeks.
"I still expect that we will have a deal in the next few weeks, but it is only prudent of course that as every day passes that we intensify preparations for no deal and that is very much what Ireland is doing," Mr Varadkar said.