Singapore's seventh President Dr Tony Tan Keng Yam leaves office today after completing his six-year tenure as the republic's head of state.

A farewell reception and ceremony for Tan, who was sworn in on Sept 1, 2011, was held at the Istana this evening.

Under Singapore's constitution, the chairman of the Council of Presidential Advisers, J.Y. Pillay, will be acting president until a new president is elected.

Nomination Day for the upcoming presidential election which will be a reserved election for the Malay community is Sept 13, followed by Polling Day, Sept 23.

The Straits Times reported today that Tan's presidency began at an unsettled time in Singapore politics.

The newspaper said the general election in May 2011 saw a swing against the ruling party. Just over three months later, the presidential election was held. Tan won by a whisker, with 35.2 per cent of the votes.

His term also coincided with important moments, including the death of founding Prime Minister Lee Kuan Yew, the nation's 50th birthday, the Little India riots, Singapore's first Olympic gold medal, and significant changes to the elected presidency, it said.

Tan also built on the President's Challenge, which began as an annual fund-raiser for the social service sector and those in need under the late president S.R. Nathan. Tan urged Singaporeans to volunteer and support social enterprises.

More than 37,000 have volunteered for the cause since 2012, it said.

Meanwhile, Prime Minister Lee Hsien Loong recalled that last year, the government had to seek Tan's consent to make one commitment to give a guarantee for the Kuala Lumpur-Singapore High Speed Rail project.

"It was to safeguard Singapore's interest in the bilateral agreement with Malaysia to build the High Speed Rail, matching a similar guarantee by the Malaysian government," he said in his speech at the farewell reception and ceremony.

"We briefed you and the Council of Presidential Advisers. You studied the issue carefully, giving us your views from the perspective of safeguarding our reserves.

"Happily, we were able to take your views fully into account in the final agreement, which we signed with your concurrence," said Lee.

Singapore and Malaysia signed the bilateral agreement at the end of 2016.

Of the entire HSR, 15 km will lie in Singapore and 335 km in Malaysia.

-- BERNAMA