Sabina Higgins has condemned the rise of right-wing, neo-fascist parties around Europe and said politics of hate and fear must be rejected.
The President's wife explained that members of the Roma community still experienced racism across Europe.
Speaking at a Roma Holocaust Memorial Day event, Ms Higgins said that poisonous ideologies had no place in modern society.
Mrs Higgins was visibly emotional during the speech at the Mansion House yesterday morning and also pointed to the hatred faced by a number of different cultures and religions.
"The recent rise of right-wing, neo-fascist parties in Europe has brought a reawakening of that anti-Roma sentiment along with anti-Semitism, Islamophobia and anti-immigrant narratives," Mrs Higgins said.
"These poisonous ideologies must not be allowed to gain a foothold in the contemporary moment.
"It's a cause of great grief that right through history so much unnecessary grief inflicted suffering on people from man's inhumanity to man.
"The politics of hate, fear and otherness must be rejected."
The memorial was first held in 2009 and marks the anniversary of the extermination of 2,897 Roma and Sinti in the gas chambers of Auschwitz-Birkenau in 1944.
It is estimated that 500,000 Roma and Sinti were murdered during the Holocaust.
"The suffering of the Roma people didn't end in World War II," Mrs Higgins said.
"The Roma people still to this day face racially motivated hate crimes, violence, persecution, deportation and discrimination in countries across Europe."
Also speaking at the event was professor Ethel Brooks, Romani activist and US Holocaust Memorial Council member.
The memorial day also heard from Roma leaders and young Roma representatives, who read out the stories of Holocaust survivors, whose families now live in Ireland.