HONG KONG - A SECOND Hong Kong child has been diagnosed with a kidney stone after drinking tainted Chinese milk, the government said Monday, as worried parents took their children for health checkups in a growing food safety scare that has spread from the mainland.

The 4-year-old boy was hospitalised in stable condition, the Hong Kong government said in a statement.

The boy, who was born in Hong Kong but lives in China, drank milk made by the Chinese dairies Yili Industrial Group Co. and Mengniu Dairy Group Co. for four months, government spokesman Lam Tsz-wai said.

Mainland doctors diagnosed him with a kidney stone, and his father took him to Hong Kong on Monday for a second checkup, which confirmed the diagnosis, the government statement said.

Melamine-tainted milk has sickened nearly 53,000 children in mainland China and is blamed for the deaths of four. The chemical is used in making plastics and is high in nitrogen, which registers as protein in tests of milk.

Hong Kong's government announced over the weekend that a 3-year-old girl had been diagnosed with a kidney stone after drinking milk made by Yili.

On Monday, worried parents in Hong Kong took their children for checkups.

About 20 parents and their children were waiting at the outpatient clinic at Princess Margaret Hospital earlier Monday.

Pang Wai-ming said his 2 1/2-year-old son has been drinking Yili milk and that of another Chinese dairy, Mengniu Dairy Group Co., for a year.

'It sounds very scary. I will feel better once my son gets checked out,' Pang said.

Another father who brought his son for a checkup who only gave his last name, Chan, said he didn't know what was safe and what wasn't.

'All he can drink is water. There's nothing else to drink,' he said of his son.

Also Monday, Hong Kong health secretary York Chow said the government would publish new laws Tuesday limiting the amount of melamine allowed in all food products.

The chemical will not be banned outright - even in goods aimed at children and pregnant women - because regulators need to factor in the possible transfer of melamine from the environment during food processing, Chow said.

Violators would face up to six months in prison and a fine of 50,000 Hong Kong dollars (US$9,057), he said. --AP