BEIJING — A New Zealand farmers' group that owns part of the Chinese dairy that produced tainted milk powder linked to the sickening of more than 430 babies said today it urged the company to recall the product as early as six weeks ago.

The statement from Fonterra Co-operative Group, which owns 43 percent of SanluGroup Co., came a day after China's health minister blamed the dairy for delays in warning the public about its contaminated product.

Chinese officials complained they were not alerted until Monday, even though Sanlu received complaints as early as March and company tests in August found the milk powder contained melamine, a chemical used in plastics that is banned in food products.

Sanlu, China's biggest milk powder producer, ordered a recall Thursday.

Fonterra, a dairy farmers' cooperative, said it had urged the Sanlu Group board to call for a full recall of the milk powder on Aug. 2, the day the board was notified — nearly six weeks before the recall action was taken.

"From the day that we were advised of the product contamination issue in August, Fonterra called for a full public recall of all affected product and we have continued to push for this all along," Fonterra said.

A Fonterra spokesman in New Zealand said its three directors on the Sanlu board had been pressing the board to take action since the contamination was first identified. The spokesman declined to be named, citing company policy.

Calls to Sanlu's head office in Shijiazhuang, a city southwest of Beijing, rang unanswered Sunday.

Chinese officials, meanwhile, defended their response to China's latest product safety disaster. They said Saturday that 19 people had been detained and 78 were being questioned about how the banned chemical was added to milk sold to Sanlu.

At least 432 Chinese babies who were fed Sanlu milk are suffering from kidney stones, Health Minister Gao Qiang said at a news conference Saturday. One baby reportedly died.

"The Sanlu Group should shoulder major responsibility for this," Gao said. He gave no indication of what penalties the Chinese dairy might face but said those responsible would "be dealt with severely."

The incident was an embarrassing failure for China's product safety system, which was overhauled in an attempt to restore consumer confidence after a string of recalls and warnings abroad over tainted toothpaste, faulty tires and other goods.

The milk scandal is especially damaging because it involves a major Chinese food company and the government expects such companies to act as industry role models for safety and quality.

Gao said some tainted milk powder was exported to Taiwan but none was sold to other foreign markets.

In Taiwan, authorities Saturday seized thousands of bags of Chinese milk powder. There was no word on whether any was consumed in Taiwan.

Liu Fang-ming of Taiwan's Taoyuan county government said a 55,115-pound (25,000-kilogram) shipment arrived in June, but that only 21,660 pounds (9,825 kilograms) had been recovered.

Chinese investigators were looking into how and why the melamine was added to milk.

Gao said it might have been done to fool quality tests after water was added to fraudulently increase the milk's volume. Melamine is rich in nitrogen, and standard tests for protein in food ingredients measure nitrogen levels.

Investigators are probing whether word of the contamination was suppressed, said Vice Gov. Yang Chongyong of Hebei province, where Sanlu Group is located.

"We will look into whether government at any level was negligent or whether any officials tried to withhold information," Yang said. "If we find anyone did this, they will be held accountable."

Gao said Beijing was sending experts to treat the hundreds of sick babies and would pay for their care.

"We are confident that with timely diagnosis and treatment, these infant patients will recover soon," he said.

Shoddy and fake goods are common in China, and infants, hospital patients and others have been killed or injured by tainted or fake milk, medicines, liquor and other products.