Explosions at fireworks plants have caused concern for the nation's work safety authorities, prompting a tightening of supervision on fireworks manufacturing.

Illegal production, sale, storage and transport of fireworks are to be targeted in the planned crackdown, said Sun Huashan, vice-director of the State Administration of Work Safety.

Sun made the remarks on Sunday while heading a team to inspect a large fireworks wholesale company based in Baoding, in North China's Hebei Province. The inspection came just three days after explosions occurred at two fireworks factories.

Last Thursday, a series of blasts ripped through seven workshops at the Jiangnan Fireworks Plant in Anhua County of Central China's Hunan Province, killing 13 and leaving four others seriously injured.

The workshops were reduced to rubble and an area of around 500 square metres was obliterated.

The accident's cause is still under investigation. The county originally had 17 fireworks factories, but eight have already been closed because of safety concerns.

On the same day, an explosion at an illegal fireworks workshop in Jinzhou, in North China's Hebei Province, killed one person and seriously injured two.

Fireworks production is a major source of revenue in many poor parts of China, but lax safety standards routinely lead to accidents.

"With the coming of the busy fireworks production season, safety management is highlighted, particularly in light of Beijing lifting its fireworks ban," Sun said.

Fireworks have been used for centuries in China to mark auspicious occasions such as festivals, weddings and business openings.

Residents of Beijing will be allowed to once again enjoy their centuries-old custom of celebrating Spring Festival, or Lunar New Year, by setting off fireworks. On September 9, the municipal legislature passed a regulation lifting a 12-year ban.

Analysts say Beijing's move might serve as a model for other cities, which might increase the risk of fireworks-related accidents.

"So, to decrease the risks of accidents, local governments must intensify their supervision of overloaded firework production as well as illegal sale, storage and transportation," Sun said.

Last week, the central government issued a document to strengthen the regulations on firework production and use, urging a standardized design of factories and warehouses featuring firefighting equipment, and tougher crackdowns on illegal production and storage.