China has dramatically raised the tally of children sickened by dairy products laced with the industrial chemical melamine to 294,000, more than five times the original figure.
In a late-night statement on Monday, the health ministry also said six babies may have died from consuming poisoned milk, up from a previous confirmed death toll of three.
The updated figures showed the problem over contaminated milk in China this year was much greater than the government had acknowledged for months, after it said in late September that just 53,000 babies had fallen ill.
Melamine is a chemical normally used to make plastics, but it emerged in September that it had been routinely mixed into watered-down Chinese milk and dairy products to give the impression of higher protein content.
Melamine can cause kidney stones if taken in excessive levels, and babies who were fed tainted milk powder suffered the worst because they consumed so much of the chemical.
The ministry said the 294,000 children who fell ill had suffered from urinary tract problems and that 51,900 of them had been admitted to hospital for treatment.
A total of 861 children remained in hospital, with 154 of them in a serious condition, according to the ministry.
The central government previously said three babies had died of kidney failure from consuming tainted milk powder, while a regional government also reported one death.
A health ministry spokeswoman confirmed to AFP on Tuesday that the six potential deaths included the three confirmed earlier.
The scandal became a global issue when news broke in September, with Chinese dairy products around the world recalled or banned after they were also found to be tainted with melamine.
No melamine-related deaths have been reported overseas and the government has taken a range of high-profile measures to fix the problem, but confidence in Chinese dairy products overseas remains extremely low.
The state-run China Daily reported on Tuesday that Chinese dairy exports had come to a near standstill, just when the industry was normally enjoying its busiest time of the year.
Only 1,036 tonnes of dairy products were exported in October, down 92 pervent from the same period last year, the newspaper said, citing the customs administration, with other industries also suffering.
"The milk food scandal has created distrust in other China-made food exports, and stunted their exports too," the China Daily said.
Premier Wen Jiabao and other Chinese leaders have repeatedly sought to reassure the world about the safety of Chinese food exports.
"We will use our actions and high quality of our food products to win the trust and confidence of Chinese people and people around the world," Wen said in October.
However it remains unclear just how much of China's food is contaminated with melamine and other dangerous substances.
A few days after Wen's comments, it emerged that some Chinese eggs also had traces of melamine, after the chemical was added to chicken feed to give the appearance of higher protein content.
The discovery raised concerns that it could be in many other Chinese foods, with the suspicion that it may have been mixed to other livestock feed.
Other Chinese foods have come under scrutiny for safety issues in recent years.
Dumplings laced with pesticide have been discovered in Japan, while the Chinese and international media have reported on problems such as steroid-laced pigs and fish being fed antibiotics so they can survive in polluted water.