Hong Kong shares plunged Wednesday as Donald Trump looked set to become US president, upending expectations market favourite Hillary Clinton would win and fuelling worries about the impact on the global economy.

The Hang Seng Index dived 2.16 percent, or 494.28 points, to end at 22,415.19.

The benchmark Shanghai Composite Index fell 0.62 percent or 19.52 points, to 3,128.37 while the Shenzhen Composite Index, which tracks stocks on China's second exchange, slumped 0.58 percent, or 11.97 points, to 2,068.47.