HONG KONG - THREE more children in the southern Chinese gambling enclave of Macau have developed kidney stones after drinking milk that may have been be tainted with the industrial chemical melamine, bringing the total number of sick children to seven, the government said.

Neighbouring Hong Kong has recently reported 10 cases in the Chinese milk scandal that has seen dairy products contaminated with melamine sickening tens of thousands of Chinese children, and is linked to the deaths of four infants.

Ultrasounds confirmed the diagnoses in the three new cases in Macau - two 6-year-old girls and an 11-year-old boy, the government said in a statement late on Tuesday.

The boy is currently hospitalised but the two girls developed small stones and did not require hospital treatment, government spokeswoman Elena Au told The Associated Press.

The two girls drank milk made by Chinese dairy Yili Industrial Group Co, Au said.

Yili's products were earlier confirmed to contain melamine.

Officials are still investigating what brand of milk the boy drank, Au said.

Separately, cake made and served at a Chinese restaurant in Hong Kong was found with excessive amounts of melamine, the government said in a statement late on Wednesday.

The company that runs the restaurant, Maxim's, didn't immediately respond to an e-mail from The Associated Press seeking comment.

Authorities in China have blamed dairy suppliers for the contamination scandal, saying they added melamine to watered-down milk to dupe quality control tests and make the product appear rich in protein.

Melamine is used in the manufacturing of plastics, fertiliser, paint and adhesives. Health experts say ingesting a small amount poses no danger, but in larger doses, the chemical can cause kidney stones and lead to kidney failure. Infants are particularly vulnerable. -- AP