"I strongly deny any involvement in this matter or anything to do with Mr Peters' personal life", Clark Hennessy said in a short statement sent to the Herald.
Hennessy has left his job at the National Party and works overseas.
Former Cabinet minister Paula Bennett confirmed she had now been served the papers through a representative.
"Looks like a worthless fishing expedition. Would have thought [Peters] had actual work to do," she responded.
Newsroom.co.nz editor Tim Murphy also labelled the legal action a "fishing expedition" and noted the papers had been signed on September 22 - the day before the election.
"Peters is seeking journalist phone records, notes, emails in regard to the stories disclosing his super windfall," Murphy tweeted.
"And copious documentation, phone records from Paula Bennett, Joyce, Eagleson, Tolley, English and Brendan Boyle.
"It is a real fishing expedition. Even the lawyers recognise [that] of the defendants 'some will have tortious liability, some will not'."
When Bill English was asked if he had been served papers, the National leader said he "hadn't seen anything".
"If he does it will be a legal matter and I won't comment."
