India on Saturday accorded former premier Manmohan Singh, one of the architects of the country's economic liberalisation in the early 1990s, a state funeral with full military honours, complete with a gun salute.

Singh, who held office from 2004 to 2014, died at the age of 92 on Thursday, after which seven days of state mourning were declared.

The honours were led by President Draupadi Murmu with Prime Minister Narendra Modi in attendance, along with the country's top civilian and military officials. Bhutan's King Jigme Khesar Namgyel Wangchuck also attended the ceremony.

Opposition leader Rahul Gandhi, who called the former prime minister his mentor and guide, joined Singh's family as they prayed before his cremation.

Earlier, mourners gathered to pay their respects to Singh. His coffin, draped in garlands of flowers, was flanked by a guard of honour and carried to his Congress Party headquarters in New Delhi.

It was then taken through the capital to the cremation grounds, accompanied by guards of soldiers and accorded full state honours.

Modi called Singh one of India's "most distinguished leaders."

US President Joe Biden called Singh a "true statesman," saying that he "charted pathbreaking progress that will continue to strengthen our nations – and the world – for generations to come."

The former prime minister was an understated technocrat who was hailed for overseeing an economic boom in his first term.

Singh's second stint ended with a series of major corruption scandals, slowing growth and high inflation.

Singh's unpopularity in his second term, and lacklustre leadership by Nehru-Gandhi scion Rahul Gandhi, the current opposition leader in the lower house, led to Modi's first landslide victory in 2014.

Born in 1932 in the mud-house village of Gah in what is now Pakistan and was then British-ruled India, Singh studied economics to find a way to eradicate poverty in the vast nation.

He won scholarships to attend both Cambridge, where he obtained a first in economics, and Oxford, where he completed his doctorate.

Singh worked in a string of senior civil service posts, served as a central bank governor and also held various jobs with global agencies including the United Nations.

He was tapped in 1991 by then Congress prime minister PV Narasimha Rao to serve as finance minister and reel India back from the worst financial crisis in its modern history.

Though he had never held an elected post, he was declared the National Congress's candidate for the highest office in 2004.

In his first term, Singh steered the economy through a period of nine percent growth, lending India the international clout it had long sought.

He also sealed a landmark nuclear deal with the United States that he said would help India meet its growing energy needs.

President Murmu said Singh would "always be remembered for his service to the nation, his unblemished political life and his utmost humility." (AFP)