The New Zealand Embassy in Beijing was alerted by Fonterra in mid-August that its Sanlu operation was "receiving" melamine contaminated milk.
Yet officials did not blow the whistle to Wellington for another fortnight.
The Ministry of Foreign Affairs and Trade released an official timeline yesterday revealing Fonterra China "gave an informal indication" on August 14 to an embassy official that its 43 per cent owned joint venture was "receiving milk contaminated with melamine".
As events turned out, the Chinese Government was not formally alerted until the New Zealand Government ordered its foreign affairs officials to warn Chinese food safety authorities in Beijing on September 9.
The ministry timeline has been released as pressure comes on the Government and Fonterra to explain why it took so long for the toxic infant formula scandal to be made public.
Four Chinese babies are dead from complications from acute kidney failure and about 1300 others are still in hospital after drinking melamine-contaminated infant formula from Sanlu.
Fonterra chief executive Andrew Ferrier said last night the company accepts the ministry's record of events.
The timeline suggests Fonterra may not have been upfront about the fact that it knew on August 2 that its Chinese company's infant formula had been contaminated with melamine.
The ministry maintains there was initially "insufficient information" to send an "authoritative" report to Wellington. But on August 22, Fonterra advised the embassy that Sanlu had a problem with contaminated product, and that the company had urged local authorities for a full product recall.
Fonterra and the embassy continued discussions over the next week with Fonterra providing confidential information over its talks with Sanlu and local authorities to try to get a product recall.
Ambassador Tony Browne phoned the ministry during August 23-29 saying Fonterra had a "sensitive problem" and sent it a report on August 31 which was discussed with Trade Minister Phil Goff two days later.
A formal report was finalised on September 5 and provided to key ministers. Prime Minister Helen Clark directed officials to attend a special meeting of ministers on September 8.
On September 9 the ambassador and other embassy staff called relevant agencies in China.
Trade Minister Phil Goff said the Government had to check that New Zealand dairy products were free from melamine contamination to protect local consumers. It needed to ensure that Chinese central authorities were "engaged and acting on it" and ensure that Fonterra took the steps needed to protect its reputation "in terms of food safety and quality".