Act leader David Seymour has denied his involvement in Winston Peters’ superannuation leak.

Peters has dropped a bombshell in Parliament, using Parliamentary privilege to claim Rachel Morton leaked information about his pension overpayment, before the last election.

Peters said Simon Bridges' former chief press secretary was there when her then-boss Paula Bennett was told about the overpayment.

He said Morton told her then-partner - ACT leader David Seymour.  Seymour then told Taxpayer Union director Jordan Williams, who told Hutt-South MP Chris Bishop's father, John Bishop, Peters alleged.

He said the information was then passed to Newsroom editor Tim Murphy and blogger David Farrar.

"Every last one of them - Morton, Seymour, Williams, Bishop, Murphy, Farrar - played dirty politics to breach my inalienable right, and the inalienable right of every New Zealander, to privacy."

Peters said he's very confident he'll win a legal fight.

“I’ve had these battles before where we’ve been overruled initially, but in my case, I am resolved to see the truth out, andthe truth will be.”

However, Seymour told Heather du Plessis-Allan that he did pass on the private information to Taxpayer Union director Jordan Williams, as he didn’t have anything to pass on.

du-Plessis-Allan asked, “So you never got it (the information) at all and passed it to anybody at all?”

• Heated scenes as Peters names alleged leakers, Seymour asked to leave the House
• 'Racist attack': Peters defends sending friends on taxpayer-funded Antarctica trip

Seymour replied, “No and the first I heard of it (the leak) was probably the same as you Heather, reading it in the press,” he said.

When challenged that he had been quoted in the same stories as those breaking the news of the leaked details, Seymour denied his involvement.

“Well can’t remember what story that was, but if I was quoted, it wasn’t from a position of knowledge, it was from a positon of commentary, just like anyone else.

“People call me and I make quotes and it doesn’t mean that you have information, it just means that you’ve got something to say.

“And as you know, a lot of journalists call me and I give commentary on the affairs of the day.”

Seymour denied that he first found out about the leak from a member of the media, saying he had “no awareness of anything until the facts were published.”

“But of course, people call me and ask me questions, then I answer to the best of my knowledge,” he said.

Asked why Peters would claim such a thing were it not true, Seymour said Peters would have a “few motivations” to lie.

“If you look at the long term, he’s at one-and-a-half per cent on the polls, his career’s finished, he’s achieved very little, he’s very desperate.

“And if you look at today, the story on the news is going to be that his friends gained access to go to Antarctica for no real reason.

“The Prime Minister’s now compromised, because she said it was all about philanthropy, but she can’t explain what philanthropic programme they were involved in.

“And of course Winston Peters’ very compromised there because he’s the minister responsible.

 “You’ve got a desperate guy at the end of his career, he’s been in parliament too long in my opinion, and now he’s trying to drag me into dirty politics for some reason.”