Former Singapore president SR Nathan, 92, passed away peacefully at general hospital at 9.48pm, according to the Singapore Prime Minister's Office.

"The prime minister and his cabinet colleagues are sad to learn of the passing of SR Nathan and would like to convey their condolences to his family," said the prime minister's office in a statement today.

It said that arrangements for the funeral and for the public to pay their last respects will be announced later.

On July 31, the prime minister's office announced that Nathan suffered a stroke and was in critical condition in the intensive care unit at the Singapore general hospital.

Nathan who was appointed as Singapore's high commissioner to Malaysia in 1988, was the longest-serving president in Singapore, and was in office for two terms from 1999 to 2011.

He officially stepped down as the sixth president on Aug 31, 2011 and was succeeded by the current President Tony Tan Keng Yam.

Prime Minister Lee Hsien Loong and President Tony Tan paid their tributes and offered condolences to Nathan's family in Facebook posts.

"Deeply saddened by the passing of SR Nathan today. He passed away peacefully at the Singapore general hospital, surrounded by family and loved ones, three weeks after suffering a stroke," Lee wrote in his Facebook.

"Nathan's life is an inspiration to us all. His was a story of how a young boy strove to triumph over his circumstances and make a contribution to society. He held many public service posts, and occupied the highest office in the land.

"Nathan was our longest serving president. He was a warm and approachable president who endeared himself to Singaporeans. He impressed visitors with his knowledge of world affairs, and served with dignity and distinction," said Lee who has known Nathan for 40 years, since he was a young officer in the Singapore armed forces.

"I remember him as a man guided by a deep sense of duty to the nation. He stepped up each time duty called. He was a true son of Singapore. My condolences to Mrs Nathan and the family. Our thoughts and prayers are with you in this time of grief," he said.

The Singapore president said that he and his wife were deeply saddened by the passing of Nathan.

"I had the privilege of working with Nathan from 1996 to 1999 when I was the deputy prime minister and minister for defence. He helped set up the Institute of Defence and Strategic Studies, which is now the S Rajaratnam School of International Studies. The school is ranked among the top think tanks in the region," Tan wrote.

Tan said that Nathan also played an active role in uplifting the Indian community when he was chairperson of the Hindu Endowment Board and founding member of the Singapore Indian Development Association (Sinda).

"As president of Singapore, Nathan championed social causes by initiating the President's Challenge in 2000. The President's Challenge gained much support from the community and raised over S$100 million for more than 500 beneficiaries during Nathan's two terms of office.

"Our thoughts and prayers are with Mrs Nathan and family during this time of mourning," he wrote further.

- Bernama