Prime Minister Narendra Modi left for India after concluding his significant and successful three-nation visit to Indonesia, Malaysia and Singapore.

External Affairs Ministry Spokesperson Raveesh Kumar said the prime minister's visit added momentum to India's Act East Policy.

"After a significant and successful three-nation visit to Indonesia, Malaysia and Singapore, PM @narendramodi emplanes for India," Kumar tweeted.

During his three-day visit to Singapore, Modi held wide-ranging talks with his Singaporean counterpart Lee Hsien Loong and delivered a keynote address at the Shangri-La Dialogue - Asia's premier defence and strategic affairs conference.

In his keynote address at the Dialogue yesterday, Modi said an "Asia of rivalry" will hold the region back while an Asia of cooperation will shape the current century.

He is the first Indian prime minister to address the Shangri-La Dialogue.

On the last day of his Singapore visit, Modi also met US Defence Secretary Jim Mattis and discussed security-related issues.

He also visited the Changi Naval Base and met officers and sailors of the Indian Navy and Royal Singapore Navy.

Modi had arrived in Singapore after a brief halt in Malaysia where he met his 92-year-old Malaysian counterpart Mahathir Mohammad to personally congratulate him on his stunning election victory and the two leaders had "productive discussions" on bolstering the bilateral strategic ties.

During his first-ever official visit to Indonesia, Modi held "productive discussions" with President Joko Widodo.

The two countries elevated their bilateral ties to Comprehensive Strategic Partnership and condemned terrorism in all its forms, including cross-border terror.

India and Indonesia also signed 15 agreements, including one to boost defence cooperation and called for freedom of navigation in the strategic Indo-Pacific region.