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.
"It is against company policy to disclose any individual customer information unless privacy law permits, and there is a legitimate business reason. Our customer records management systems are regularly audited," the spokesman said.
Ms Chuang said she received an anonymous text just days before the mayoral election, warning her off going public with her revelations.
It said: "You should be more careful what you share with the slaters [Whale Oil blogger Cameron]. Any hope you have of a career in public office just disappeared along with your human decency."
Last week, the Herald appealed for information on who sent the text. If you can help, email firstname.lastname@example.org or phone (09) 373- 6048.