The Taoiseach Leo Varadkar has congratulated the new leader of Austria, Sebastian Kurz.
In a tweet, Mr Varadkar said he contacted Mr Kurz to congratulate him on becoming chancellor.
He also noted that he is "no longer the youngest of the bunch" of EU leaders.
— Leo Varadkar (@campaignforleo) December 16, 2017
Austria will become the only western European country with a far-right party in government.
The anti-immigration Freedom Party has agreed a coalition with the conservative People's Party, after two months of talks.
The agreement means Mr Kurz will become the world's youngest leader, at 31 years of age.
Austrian journalist Tessa Szyszkowitz is not surprised he has turned to the far-right for support.
"There is this difference between his young, fresh-face and his politics.
"He is himself more conservative, in many ways, than we thought".