On Wednesday, the Prime Minister said he wouldn't "go into names".
This story has been updated after the Prime Minister's office corrected the dates Burgess held the role of chief policy adviser.
The staffer who received a document from Fonterra and Z Energy - that made suggestions for a potential law change - was a senior adviser in the Prime Minister's Office.
The Prime Minister's chief policy adviser Matt Burgess received the briefing note, which had been delivered in hard copy in mid-2024.
Burgess was in the role in the Prime Minister's office (PMO) between January 2024 to October 2025, and had previously worked at the New Zealand Initiative think tank as senior economist.
