ACC claimant Bronwyn Pullar remains in dispute with the Accident Compensation Corporation over what took place at a meeting in December last year.
The corporation asked police to investigate what happened at the meeting between Ms Pullar, her support person Michelle Boag and two ACC senior managers.
Bronwyn Pullar was mistakenly emailed details of 6500 ACC claimants. At the meeting, ACC staff said the Auckland woman threatened go to the media about a privacy breach unless she was guaranteed a benefit for two years. Ms Pullar has strongly denied this.
On Tuesday, police said that no action will be taken and no offence was committed at the meeting.
Assistant Commissioner Malcolm Burgess said that, after careful consideration of the evidence now available and a separate legal review of the facts, police have determined that no offence has been disclosed.
Mr Burgess said there would be no further police investigation into the concerns raised in March this year.
ACC accepts the outcome of the investigation, but board chairman John Judge said ACC's original report on the meeting was complete and accurate, and staff considered that a threat had been made.
But Bronwyn Pullar says the report was not accurate, nor complete. In a statement on Tuesday, she said ACC knows the threat never happened because they have heard a recording she made of the meeting.
Ms Pullar believed police made the right decision not to take any further action. She said she did not expect any other outcome, and it is regrettable that police time was wasted.
Friend and former National Party president Michelle Boag on Tuesday reiterated that Bronwyn Pullar did not make a threat.
Ms Boag told Radio New Zealand's Checkpoint programme she is pleased but not surprised at the police decision and is waiting for an apology from ACC.
"The police have confirmed Bronwyn's version of events. ACC are quite happy to apologise to 6500 who they've wronged through a privacy breach. They made an allegation of criminal behaviour against me and Bronwyn - even though the police have said there is none - they're not happy to apologise to us."
The Auditor-General and the Privacy Commissioner are also investigating.
ACC defends police involvement
The Accident Compensation Corporation on Tuesday defended its decision to refer the Bronwyn Pullar case to police.
Chief executive Ralph Stewart said the corporation was obliged to seek an independent opinion of what happened at the meeting.
"Referring the matter was the right thing to do, given the seriousness of refusing to return confidential information that had been received in error. Should ACC be confronted with a similar situation, the same action will be taken."
Mr Stewart said the corporation has a zero tolerance for wrong-doing and it has contacted and apologised to 98% of clients affected by the privacy breach.
The matter is closed and efforts are now focused on improving ACC's privacy systems, he said.
"Trust and confidence in ACC has been damaged as a result of the privacy breach. We agree and accept that; it's what we do now that matters. It's what we do to improve and make ACC safe and confident again for the clients' information."
ACC Minister Judith Collins has not commented, except to say the corporation must continue to work to rebuild public trust and confidence.