Hong Kong on Saturday recorded its hottest day since authorities began taking temperature readings 130 years ago, due to the influence of a nearby typhoon.

The daily maximum temperature hit 36.3 degrees Celsius, the Hong Kong Observatory said, with higher temperatures recorded in some parts of the city earlier in the day.

A layer of haze hung over the metropolis of seven million, as people wielding electric fans and umbrellas tried in vain to beat the boiling heat.

"This is a new record," a Hong Kong Observatory spokesman told AFP.

"Today, the recorded daily maximum... was 36.3 degrees Celsius," he said, adding that the previous hottest days on record occurred in 1900 and 1990, when a temperature of 36.1 degrees Celsius was recorded.

The former British colony began officially recording temperatures in 1885.

"Under the influence of the outer subsiding air of Typhoon Soudelor, it was very hot over the territory," the observatory said on its website, urging people outdoors to "drink plenty of water".

Typhoon Soudelor ripped up trees and triggered landslides in Taiwan, and knocked out power to 1.5 million homes, before churning towards China.

Taiwanese authorities said four people had died in the storm, including a firefighter in southern Pintung county and a man in the coastal town of Suao who was hit by a falling billboard.