ACC board chairman John Judge has assured Judith Collins no one at the organisation leaked the personal information of claimant Bronwyn Pullar.
ACC Minister Judith Collins this morning appeared reluctant to express full confidence in Judge, although she stopped short of blaming him for what appears to have been a breach of Pullar's privacy.
Collins, Minister for ACC, called Judge into a meeting last night.
Pullar came to the media's attention after it was revealed ACC had accidentally sent the details of 6000 claimants to a third party.
She was named as the recipient of the breach and revealed she had been supported by former National Party president Michelle Boag in a meeting with ACC over her case.
Collins this morning said that information had "certainly not" come from her office and, after her meeting with Judge, this afternoon said the information had not come from ACC.
"He assured me that it hadn't come from ACC."
Asked how he could ensure that, Collins said that was a matter he needed to address.
Chief executive Ralph Stewart had also told the minister he had not leaked the information publicly.
"We've got a privacy commissioner's review of this and bear in mind we have a police investigation around that meeting in December and what's happened since, so I'm sure that's going to form part of what they're looking at."
Collins said the one senior staff member who had received the information had only passed it on to Judge and Stewart.
"I know that it did not come from me or from the one staff member that she sent it to, it did not go round my office, it didn't go round anywhere else and I know that for certain."
She also said she could not see why Boag, a National Party insider and Pullar's friend, would leak the information.
If Pullar had any concerns about her privacy she should contact the Privacy Commissioner or police, Collins said.
Asked this morning if she had confidence in Judge, Collins said: "I've got a lot of confidence in the work that he's done in the board, particularly around the financial state of ACC. But look, I'm very concerned about the privacy issues and I spoke to him last night, had him in my office to talk about this issue. I'm very concerned about the privacy issue and I expect it to be dealt with."
Collins said she would not "speculate" over the source of the leak.
"People can speculate all they like but I'm also aware that it didn't come from my office and it didn't come from me - I'm 100% certain."
Labour's deputy leader Grant Robertson said there were only a few ways the information could have been leaked and Collins needed to answer questions.
He had no details but Labour would be asking questions in Parliament.
"We need to find out more about how information about Ms Pullar found its way into the public arena."
There were only a few ways the information could have got out, Robertson said.
"Judith Collins needs to answer very clearly whether her or her office had any role in accessing that information or in how that information made its way into the public arena."
Labour wanted a full inquiry into ministerial conduct, the conduct of the ACC board and the privacy issues.
The inquiry was bigger than what the Privacy Commissioner or police could look at and the auditor-general should be involved, he said.