Taiwan is preparing for a potentially severe impact from Typhoon Koinu, which is expected to make landfall on the south-eastern coast near the city of Taitung on this morning (5 October) as a category three typhoon.

The storm was headed towards southern Taiwan on Wednesday bringing heavy rain and winds and causing the cancellation of more than 100 flights as well as the suspension of work and schools.

The heaviest rain is expected to fall along mountainous and sparsely populated parts of Pingtung county in the south and the east coast counties of Taitung and Hualien, but the typhoon will also affect the major southern port city of Kaohsiung.

In Taitung, fishermen secured their boats in port, as waves gradually became more intense along Taiwan’s east coast.

Kaohsiung and its neighbouring city of Tainan said they would suspend work and classes from 6 pm (1000GMT) on Wednesday and all day on Thursday.

Taiwan’s capital Taipei was lashed by squally rain showers, but was not expected to be badly affected. Offices and schools remained open as normal.

Taiwanese airlines cancelled 87 domestic flights, while 25 international ones were also cancelled, the transport ministry said.

After passing through Taiwan, the typhoon will head towards southern China’s Guangdong and Fujian provinces and then Hong Kong, where it is likely to weaken further to become a tropical storm.

Hong Kong’s Weather Observatory said Koinu will enter within 800 km (500 miles) of the financial hub on Wednesday afternoon (4 October). The observatory will issue the lowest typhoon signal, 1, on Wednesday night.

A “very hot weather” warning was issued at about 7am on 4 October and authorities told the public that they should avoid prolonged outdoor activities and stay in shaded areas as much as possible.

The Observatory said Koinu was expected to move across the southern part of Taiwan towards the coast of eastern Guangdong.

“It will then move westwards, edging closer to the vicinity of the Pearl River Estuary,” it added. “Koinu’s outer downdraft is bringing generally clear skies and extremely hot weather to South China.”