A Holocaust surivor who lost scores of relatives to World War II Nazi death camps, Wiesenthal is remembered as a man who pursued the perpetrators to all corners of the globe with an unrelenting tenacity.
"He was the conscience of the world," Aver Shalev, the director of Israel's Holocaust memorial, said in Jerusalem on hearing of his passing away on Tuesday.
"The Jewish people and all of humanity owe a lot to him because he acted systematically and very strongly ... . He will be remembered as a symbol for the Jewish and human conscience, the need to protect moral values."
Wiesenthal helped to bring more than 1100 Nazi criminals to justice including Adolf Eichmann, an architect of Hitler's Final Solution, who was tracked down by Israeli agents in Argentina in 1960.
Symbol of morality
Israeli President Moshe Katsav, on a visit to Latvia, said Wiesenthal was a symbol of morality who had left the world a better place.
"Simon Wiesenthal was the biggest fighter of our generation. He represented the morality of humanity; he represented the free world, the democratic world," Katsav said.
The Anne Frank Foundation, which honours the memory of a young German Jewish girl whose diary of her family's two years in hiding from the Nazis is one of the most compelling accounts of Nazi terror, said Wiesenthal's tireless efforts helped track down the Gestapo officer who finally arrested them in Amsterdam in 1944.
Wiesenthal (R) brought at least
1100 Nazi criminals to justice
"He is the one who, after a search of many years, found Karl Joseph Silberbauer... Simon Wiesenthal devoted his life to hunting down Nazis," the foundation said in a statement.
Rabbi Marvin Hier, the founder of the Los Angeles-based Simon Wiesenthal Centre, remembered Wiesenthal as an untrained investigator who pursued fugitive Nazi war criminals with "sheer tenacity."
"He [Wiesenthal] lost 89 members of his family, in the Holocaust," Hier said.
"I wondered how he could go on. He was doing it for his grandchildren, because if not, tomorrow murderers would take inspiration from the Nazis."
His greatest legacy was to "show the world what a single man can accomplish", said Hier. "He did it all alone - nobody helped him at first."
"[Wiesenthal] was an untiring fighter for justice and law"
In Poland, scene of some of the worst Nazi death camps, former president and Nobel Peace Prize winner Lech Walesa said Wiesenthal's passing was "a huge loss which has robbed the world of another honest man".
"Even from heaven, he will continue to bring justice to the perpetrators of evil," Walesa said.
French President Jacques Chirac praised Wiesenthal as an "untiring fighter for justice and law", while French historian Marc Knobel, who worked with Wiesenthal, described him as a frail old man with an indomitable spirit.
"Wiesenthal was a little, frail, fragile man with poor health, who spoke German with a little voice and a strong (eastern European) accent," said Knobel of the French Jewish Council.
But despite his physical frailties, "he had a perspicacity, a tenacity and a courage that was exemplary", Knobel said.
Austrian Chancellor Wolfgang Schussel said Wiesenthal was the embodiment of the phrase "Lest We Forget". "We have lost an indefatigable fighter against forgetting," he said.
Terry Davis, secretary-general of the Council of Europe, said Wiesenthal was not on "a quest for revenge".
"It was a quest for justice," he said.
"He was a soldier of justice, which is indispensable to our freedom, stability and peace. It was people like him who helped us to build Europe as we know it today."