Chinese officials knew for weeks about sales of chemical-tainted milk powder that has killed two infants and sickened 1,253, but did not act until the New Zealand government pressed Beijing, New Zealand's prime minister said yesterday. The sale of tainted infant formula by Sanlu Group, the Chinese producer 43 per cent owned by Fonterra Dairy Co-operative of New Zealand, was reported for the first time by state media last week, sparking panic and outrage among parents. Sanlu was ordered to halt production and issue a general recall on Thursday after investigators found that the chemical melamine - which is normally used in plastics, fertilisers and cleaning products - in its milk powder was causing kidney stones in infants. By yesterday morning, 1,253 children had been diagnosed with illnesses linked to the powder, with 340 still in hospital and 53 "relatively serious" cases, Ma Xiaowei, Chinese vice-minister of health, said yesterday. At the weekend, officials said 432 children were ill. Melamine is the same chemical that was found in tainted pet food exports from China to the US that killed thousands of pets last year. The Sanlu board, which has three Fonterra directors, was told of contamination on August 2 when a trade recall began, said Andrew Ferrier, Fonterra's chief executive,yesterday. A public recall did not start until nearly six weeks later. "[Fonterra] have been trying for weeks to get an official recall and the local authorities in China would not do it," Helen Clark, New Zealand's prime minister, said on television yesterday. "At a local level . . . I think the first inclination was to try and put a towel over it and deal with it without an official recall." She said that once Fonterra had made the New Zealand government aware of the situation, the country's ambassador contacted senior government officials in Beijing, at which point central authorities reacted. Chinese media first reported babies were falling ill after drinking Sanlu formula on September 10 and a recall of all Sanlu products made before August 6 was issued on September 11. Sanlu first received complaints in March that its products were making babies sick and public complaints to China's General Administration of Quality Supervision, Inspection and Quarantine were made as early as June, according to Chinese media reports. A directive from China's propaganda department that was posted by an anonymous blogger during the Olympics forbade Chinese media from reporting on a number of sensitive topics, including food safety issues. On September 2, just one week before the scandal broke, China's state television aired a programme that hailed Sanlu as a model of manufacturing quality and product safety, according to media reports. The government has detained 19 people in connection with the case, but no Sanlu employees, according to Mr Ferrier. The most likely culprits are dealers who collect milk from farmers and supply it to Sanlu. They may have diluted it and added melamine, which can make milk's protein level appear higher than it is. Sanlu could not be reached for comment yesterday, but Mr Ferrier defended Fonterra's role, saying "as a minority shareholder [the company] had to continue to push Sanlu. Sanlu had to work with their own government to follow the procedures that they were given." However, New Zealand's Green party said Fonterra should have gone public much earlier. Copyright The Financial Times Limited 2008