A trio of health experts have launched defamation case against Whale Oil blogger Cameron Slater and tobacco lobbyist Carrick Graham.
Prof Doug Sellman of the University of Otago, Prof Boyd Swinburn of the University of Auckland and anti-smoking activist Shane Bradbock say Slater and Mr Graham have for "some years" been publishing "articles with a negative focus on various public health experts and advocates".
Much of the pair's work was revealed in Nicky Hager's 2014 book Dirty Politics.
"We had hoped things would change, but the various articles and comments remain live on Whale Oil, and Mr Slater has continued to publish further material," says Prof Swinburn.
"Accordingly, we have decided to bring these proceedings to address what we claim is a campaign of deliberate and sustained defamation."
The trio say they will be making no further comments until the case has been dealt with by the courts.
Mr Graham told Fairfax he was "surprised" by the case as he has been "friendly" with Prof Swinburn in the past, but would not comment on the accusations themselves.
Prof Swinburn teaches population nutrition and global health, Prof Sellman heads the National Addiction Centre, and Mr Bradbock last year joined Pharmac's consumer advisory committee and is a longtime anti-smoking activist.