The fire started in the early afternoon at the World Trade Centre on Gloucester Road in the city's popular Causeway Bay shopping district, according to a government notice

People walk out from the World Trade Centre, which is located in the city's popular Causeway Bay shopping district of Hong Kong, Wednesday, 15 Decembe

Dozens of people were trapped on the rooftop of a Hong Kong skyscraper after a major fire broke out on Wednesday, as firefighters rushed to rescue them and put out the blaze.

The fire started in the early afternoon at the World Trade Centre on Gloucester Road in the city's popular Causeway Bay shopping district, according to a government notice. The 38-story building houses both offices and a mall.

At least 12 people were sent to hospital for treatment, according to authorities.

Firefighters had used an extendable ladder to rescue several people who were trapped on the lower floors of the building. Other people were said to be trapped in restaurants in the mall, according to the local South China Morning Post newspaper.

Nearly a hundred people had also evacuated to the top of the building while waiting to be rescued. Many of them later left the building. Some of them were covering their noses and mouths but did not appear to be seriously injured.

The fire was upgraded to a level three incident, according to a police notice. Fires are graded on a scale of one to five, with five being the most severe. As of 3.06 pm, authorities said the fire was under control.

Two breathing apparatus teams and two water jets were mobilised to help fight the blaze, police said.