As the flame was kindled in the 2,600-year-old Temple of Hera at Ancient Olympia, International Olympic Committee president Thomas Bach and Rio organisers sought to rally support.

Bach said the Rio Games will be held "in a world shaken by crises" but hailed preparations for the first Olympics in South America.

"Brazilian people will enthusiastically welcome the world and amaze us with their joy of life and their passion for sport," he predicted.

"Despite the difficulties that Brazil is facing today, the flame is a timeless reminder that we are all part of the same humanity," Bach said.

Brazil's President Dilma Rousseff cancelled her attendance as she battles threatened impeachment proceedings.

In her place, Rio 2016 organising committee chairman, Carlos Nuzman, said the flame "brings a message that can and will unite, our dear Brazil."

"Brazil is ready," Brazil's acting sports minister Ricardo Leyser told reporters after the ceremony.