People hold up Singapore banners during Singapore's Golden Jubilee celebration parade at Padang near the central business district August 9, 2015. [Photo/Agencies]

The official logo for the celebration is a red dot, a symbol of pride and defiance since the 1990s, when an Indonesian leader reportedly called Singapore "a little red dot" on the map. The image, with "SG50" in white characters, is ubiquitous, adorning banners, buses, cakes and a host of goods in shops.

A recording of Lee Kuan Yew reading the Proclamation of Independence, the document that announced Singapore's separation from Malaysia, was played on radio and television channels at 9 am (0100 GMT)

Prime Minister Lee is widely expected to call the next election as early as September. His party suffered its worst-ever showing in the last parliamentary election, in 2011, with voters discontent over a widening wealth gap, sky-rocketing property prices and an influx of foreign workers.

Political analysts expect Lee's party to win more votes this time, thanks in part to the after-glow of the anniversary celebrations and in part to government efforts to address issues irking the public.

Still, when the banners are taken down, Singapore will return to debates over how to keep the economy growing while combating a low birth rate, anger over prices and a backlash over many years of liberal immigration policies.