The product came from Jingshan Pengchang Agricultural Products, a processing plant in the central Chinese province of Hubei, Hong Kong's Centre for Food Safety (CFS) said in a statement.

'The medium-sized egg sample was taken from a restaurant. Based on the level detected, people are advised to stop consuming the product concerned,' the statement, released late on Tuesday, said.

'The CFS has sent warning letters to the food premises and distributor concerned and asked them to stop using and selling the product.'

The centre found 2.9 parts per million (ppm) of the chemical in the egg sample, which exceeded the legal limit in Hong Kong of 2.5 ppm.

A three-year-old child would have to eat about 24 of the tainted eggs before the amount of melamine would become dangerous, the centre said.

An adult weighing 60 kilogrammes would have to consume 283 of the eggs before reaching the danger level, the statement said.

On Tuesday, Hong Kong's food safety watchdog said tests showed Select Fresh Brown Eggs produced in the northeastern city of Dalian contained melamine.

Retail giant Wal-Mart said on Tuesday it had pulled eggs from the producer off its shelves in its Chinese stores.

Four children have died and 53,000 fallen ill in China after drinking milk or milk products laced with melamine, which is usually used to make plastics.

Some manufacturers had been using the chemical to make watered-down milk appear to have a higher protein content.

An array of China-made foods and drinks have been removed from store shelves around the world since the contamination first came to light. -- AFP