Speaker Trevor Mallard calls off inquiry into Simon Bridges' expenses leak

Speaker Trevor Mallard is calling off the inquiry into the leaking of Simon Bridges' expenses, saying it's a National Party matter and not something the country or the Parliament needs to be involved in.

Mr Bridges, Mr Mallard and Newshub's political editor Tova O'Brien were sent a text from the leaker last Thursday calling for the inquiry to be called off.

The leaker identified themselves as a member of the National Party caucus and gave examples from the caucus meeting to prove it.

In the text, the leaker says: "You [Mr Bridges] told [an MP] in front of everyone that you thought it was the Speaker that leaked the information."

They said they had a "prolonged serious mental illness" and pleaded for the investigation into their actions to be dropped.

The Speaker yesterday appointed Queen's Counsel Michael Heron to head the inquiry into who leaked Mr Bridges' expenses to Newshub, but that inquiry has now been called off.

The Speaker, who is currently in the United Kingdom, has told Newshub that he feels conflicted because of the suggestion by Mr Bridges that Mr Mallard or his office were responsible for the leak.

"The text is from someone who is clearly very disturbed and today's publicity will almost certainly make that worse. My priority is to get appropriate support to them whether they are an MP or a staff member," Mr Mallard said in a statement. 

"I have discussed my decision with Hon Simon Bridges. He disagrees with it. He wants the inquiry to continue. I have indicated to him that the Parliamentary Service will cooperate if he decides that he wants to proceed with an investigation and appropriate consents from MPs are in place."                               

Mr Bridges called a news conference on Friday morning to insist that the investigation continue, despite concerns raised by the leaker about their wellbeing if the investigation were to continue.

"I was very worried by the text," he said.

"My utmost concern was for the wellbeing of this person.

"We're not cold-hearted people. We want to help in National."

Mr Bridges says he went to police and shared the text out of concern for the person's safety.

He says police have worked out their identity and have made it clear the person is receiving the help they needed.

"On Sunday evening police contacted me. They knew and had worked out the identity of the person concerned," he says.

Mr Bridges has called into question whether the leaker is a National MP saying there are a "range of credible scenarios" as to who the person is, including an MP, a staffer, a member of Parliamentary Services or a person in the "wider system".