A leading Chinese poultry company said Monday it had sacked four employees suspected of being involved in a food safety scandal that saw diseased ducks sold to unsuspecting consumers.

The case is the latest in a long list of high-profile food safety problems to hit China that have included pork deliberately laced with chemicals, dyed buns and tainted milk.

Huaying Agricultural, which calls itself the "World's Duck King", announced the sackings after media reported last week birds that had died of disease before slaughter had found their way to consumers.

Employees of Huaying, based in the central province of Henan, sold the ducks to businessman Cui Jinping who processed them in an underground, or "black", factory for resale as meat, reports said.

Huaying said it had fired a department manager, the head of two of its farms and two other workers over the case, according to a statement to China's Shenzhen stock exchange, where the firm is listed.

Cui will face criminal prosecution, it added.

"This has hurt the image of the company and we sincerely apologise to investors and consumers," Huaying said.

The firm's shares were down 1.29 percent to 18.37 yuan ($2.92) by midday on Monday.

The government of Henan's Huangchuan county, where the company is based, confirmed the dismissals, which it said followed an investigation by local officials.

China's central government has repeatedly vowed to improve food safety, but scandals still occur due to weak enforcement and unscrupulous business practices.

Milk was at the centre of one of China's biggest food safety scandals in 2008 when the industrial chemical melamine was found to have been illegally added to dairy products to give the appearance of higher protein content.

At least six babies died and another 300,000 became ill after drinking the tainted milk.