Singapore's founding leader Lee Kuan Yew will be given an elaborate state funeral after a week of mourning for the man who led the city-state to independence 50 years ago.

Tens of thousands of people are expected to line a 15.4-kilometre route to bid farewell to the authoritarian leader who served as prime minister for 31 years and turned Singapore into a global financial powerhouse.

Lee died on Monday aged 91 after seven weeks in hospital for severe pneumonia.
He became Singapore's first prime minister in 1959, when the island gained self-rule from colonial ruler Britain.

Singapore became a republic in 1965 after a brief and stormy union with Malaysia.

Lee stepped down in 1990 in favour of his deputy Goh Chok Tong, who in turn was succeeded by Lee's son, the current Prime Minister Lee Hsien Loong.

More than 415,000 people, equivalent to 12 per cent of Singapore's citizens, have filed past his coffin in an overwhelming show of sympathy never seen before in the country.

Shortly after midday, Lee's dark brown wooden casket, draped in the red-and-white Singapore flag, will leave parliament, where his remains have been lying in state since Wednesday.

The casket will be borne in a glass case atop a gun carriage pulled by an open-topped ceremonial Land Rover for a procession that will pass by landmarks associated with the British-trained lawyer's political career.

Lee will be given a 21-gun salute, as well as a flypast of four F-16 fighter jets from the Air Force's aerial display team, the Black Knights.

Sirens will sound for the population to observe a minute of silence for their former leader.

The motorcade will end at the National University of Singapore for a funeral service graced by Asia-Pacific leaders and other dignitaries, followed by a private cremation.

Australian Prime Minister Tony Abbott, Japanese Prime Minister Shinzo Abe, South Korean President Park Geun-hye, Indian Prime Minister Narendra Modi, Indonesian President Joko Widodo, Malaysian King Sultan Abdul Halim Mu'adzam Shah and Brunei's Sultan Hassanal Bolkiah are among the leaders attending the funeral.