National Party insider Michelle Boag acted as the support person for the ACC whistleblower during the pivotal meeting that has been referred to police.
Boag sat with her friend Bronwyn Pullar during a meeting in December in which the Auckland woman first told ACC there had been a privacy breach.
A report from ACC to its minister Judith Collins on Friday said Pullar threatened at that meeting to tell media of the privacy breach if she wasn't guaranteed two years on a benefit. The report said the corporation should have gone to police at the time; it referred the matter to police only on Tuesday.
Boag is a significant figure in National Party circles, having led as president in 2001 and 2002 the renewal process that brought Prime Minister John Key into Parliament.
Boag said it was important to realise a formal complaint had not been made to police. However, she told the Herald on Sunday: "I would be drawn into it. I was in that meeting."