UPDATED 11.12PM: The Prime Minister's office has moved to correct comments made by John Key regarding the 1080 infant formula blackmail threat.

Yesterday Mr Key told media it was the Department of Prime Minister and Cabinet that was first told of the threat by Fonterra chief executive Theo Spierings.

"My understanding of it is that phone calls made by Theo Spiering, the head of Fonterra, his office to the head of the Department of Prime Minister and Cabinet. That happened pretty much the day they got the letter."

It's now emerged Mr Key's comment was wrong.

His office says both DPMC and the police were informed around the same time, but police were told of the threat first.

Police have received around 200 calls and emails from members of the public, and they maintain their investigation is ongoing, pursuing numerous lines of enquiry.

In the meantime, the advice to parents and retailer remains the same - be vigilant, and if there's any sign of tampering on packaging, contact police.