BEIJING (AFP) — A government in northeast China kept quiet the discovery of melamine-tainted eggs for weeks and ordered a media ban before Hong Kong authorities finally revealed the problem, state press said Thursday.

The animal sanitation inspection department of Liaoning province suspected the tainted eggs came from chicken feed and ordered an investigation into the Mingxing Feed Company as early as October 6, the Beijing News said.

The discovery of melamine-tainted eggs was announced by Hong Kong food safety authorities on October 26, with the contaminated products being traced to Liaoning's Hanwei Group, one of China's largest egg producers.

The scandal has resulted in eggs being pulled off shelves in Hong Kong and China amid growing fears that a melamine-tainted milk scandal, which has left four babies dead over 53,000 others ill, has spread to other foods.

The Beijing News further said it had found a document from the Liaoning sanitation department dated October 22 that explicitly called for a media ban.

"No media interviews on this issue shall be accepted," the paper quoted the document as saying.

Police have now taken into custody the manager of the Mingxing Feed Company, the Beijing News said, citing the manager of the Hanwei Group.

The milk scandal, which emerged last month after it was similarly covered up for months, has crippled China's dairy industry and left confidence in the nation's food safety system in tatters.

Melamine, largely used for plastics and fertiliser, falsely increases the appearance of protein in milk and animal feed.

It can cause kidney stones if taken in large amounts, such as with the babies who drank tainted milk powder regularly.

The US Food and Drug Administration has set a level of melamine in food that is safe for adults, but has not set a standard for children.

Melamine was at the centre of a China-produced pet food scandal that reportedly left numerous animals dead in the United States in August 2007.

The industrial chemical has also been found in farm-raised fish, allegedly from fish feed produced in China.