"In the 20th century, Gandhi was perhaps mankind's biggest gift. In the last century, through his life and personality, he showed what the future would be. He in fact used to say my life is the message," Modi said in his address in the South Korean capital.

"This occasion assumes greater significance since we are celebrating Mahatma Gandhi's 150th birth anniversary and the world is finding in Gandhi's principles a future for mankind's interests," he added.

A later tweet by the Prime Minister's office quoted him as saying: "The thoughts and ideals of Bapu have the power to help us overcome the menace of terrorism and climate change -- two challenges humanity faces in these times.

"Through his lifestyle, Bapu showed what living in harmony with nature is. He also showed that it is important to leave a clean and green planet for the future generations."

Modi's address was followed by that of former UN Secretary-General Ban Ki-moon, who spoke of Gandhi's birthday -- October 2 -- as the International Day of Non-Violence, adding that he was honoured to be part of the celebrations of Gandhi's 150th birth anniversary.

Modi is on a two-day state visit to South Korea where he will accept the Seoul Peace Prize and have business and political engagements. He will also address the India-Korea business symposium.