Japanese Prime Minister Shinzo Abe called Mr Lee Kuan Yew "one of the greatest leaders of modern times that Asia has ever produced".
"With his incomparable leadership and unparalleled insights, His Excellency Mr Lee Kuan Yew played, for more than half a century and throughout his life, a key role not only in achieving Singapore’s remarkable economic growth and prosperity but also in securing peace and stability of the Asia Pacific region and the world. He was highly revered all over the world," Mr Abe said in his condolence message on Monday.
He added that Mr Lee had frequently visited Japan during his tenure as Prime Minister of Singapore, and that he had "made outstanding contributions in the advancement of today’s good and close relations between Singapore and Japan".
"I still vividly remember how much I was impressed by his profound wisdom, including when I met him in person in 2014," he said.
Mr Abe expressed deep sympathy and condolences on behalf of the Japanese government to Prime Minister Lee Hsien Loong, his family and the people of Singapore.
"The demise of such a great leader is indeed a great loss not only to your country (Singapore) but also to the entire international community."
Japan's Foreign Minister Fumio Kishida also released a statement, saying that Mr Lee "is not only credited for building Singapore into one of the wealthiest nations of the world as the country’s first Prime Minister but also, with his outstanding wisdom, played a key role in securing peace and prosperity in the Asia-Pacific region and the world for more than half a century."
"Together with so many around the world, the Government of Japan mourn the grievous loss of a great leader," said Mr Kishida.