At least 36 people are now known to have died in the blast, which injured 160 people; 30 others are still missing.

Around 160 people were injured by the blast

The explosion is the latest in a string of accidents at the plant, which is situated in the southern province of Guangdong, and in the province as a whole.

Fatal fireworks explosions in China, which invented fireworks more than 1,000 years ago, are common, particularly around the Chinese New Year in January or February.

The Guangdong authorities said that lighter and match factories must close as well as the 400 or so fireworks factories situated in the province.

Sparks

Plants that passed a safety inspection would be allowed to re-open, except for those in densely populated areas which would be closed permanently, an official said.

[The explosion] shattered the roofs, windows and walls of buildings 1km away

Xinhua news agency

The Tuqu factory where the explosion occurred, in the city of Jiangmen near the former Portuguese colony of Macau, had been ordered in April to improve its safety systems, but ignored the order.

The official Chinese news agency, Xinhua, said that investigators believe that sparks made by workers pounding iron nails may have caused the fatal blast.

It levelled the two-storey building, which covered an area of 3,000 square metres.

Xinhua said it "shattered the roofs, windows and walls of buildings 1km away" and "trees and utility poles were uprooted or snapped in half".

All those killed are believed to be factory workers.

The factory, which was located in a sparsely populated suburb, was run by a Hong Kong firm.

In March, an explosion at a fireworks factory in the eastern province of Jiangxi killed 33 people.