National Party leader Simon Bridges has confirmed that he received a text from a person claiming they leaked details of MPs' expenses.
Bridges was speaking at a news conference on Friday morning after it was revealed that a person claiming to be the leaker had made contact with Bridges pleading to not be named.
Bridges says the person made contact last Thursday saying they feared exposure because they had ongoing mental health issues.
He contacted police, who confirmed on Sunday that they had identified the person who sent the message. Bridges said he didn't know who the person was.
The party also sought advice from mental health professionals as to how to handle the situation.
The anonymous text message was sent to the National leader, as well as Speaker Trevor Mallard. In it the author claimed to have leaked the report to Newshub but also asked not to be identified, and said they had mental health issues.
It's understood the person said they were a member of the National Party and that they leaked the information because they disagreed with Bridges' leadership and wanted him to be held responsible for "wasting" taxpayers' money, RNZ reported.
Newshub reported earlier this month that Bridges had spent more than $100,000 on travel and accommodation over the past three months.