Vodafone has sent some of its staff a warning about delving into records after the Herald's hunt for the sender of an anonymous and threatening text to Bevan Chuang.
The text was sent from an 021 number and warned her not to go public with details of her affair with Auckland Mayor Len Brown.
A spokesman for the telecommunications giant said: "We regularly update our customer service agents, and the email was a timely reminder of our company security policy - particularly relating to accessing and disclosing customer information."
He said the internal email referred to a story in the Herald but he did not go into detail.
No staff member had yet faced any disciplinary action in relation to the hunt for the sender of the text.