Boyd Swinburn (left) and two other health researchers are pursuing a defamation case against Cameron Slater (right) and Carrick Graham.

Three top health professionals have lodged a defamation claim against blogger Cameron Slater and PR consultant Carrick Graham alleging a long running campaign against them on the Whale Oil website.

Auckland University professor Boyd Swinburn, Otago professor Doug Sellman and the director of Maori agency Shane Bradbrook said they had filed proceedings in the High Court at Auckland on Monday.

The trio said in a statement their proceedings related to blog posts and comments published on the Whale Oil website over a number of years.

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In the statement Sellman, Swinburn and Bradbrook said: "Whale Oil has published articles with a negative focus on various public health experts and advocates.

"It was not until the book Dirty Politics was published in August 2014 that it became clear Carrick Graham was involved in the publication of material on Whale Oil.

"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.

"Accordingly, we have decided to bring these proceedings to address what we claim is a campaign of deliberate and sustained defamation."

Dirty Politics is a book published by journalist Nicky Hager in 2014 based on emails hacked from Cameron Slater which alleged a network of National Government MPs and lobbyists using Slater to publish attack articles against opponents.

Carrick Graham, Managing Director of the firm Facilitate Communications, confirmed his company had been served with a notice of the defamation suit and was reviewing it.

He said he was "surprised at this move considering that over the past few years there has been a number of interactions with Professor Swinburn which were friendly and at no stage have concerns been raised with me.

"It is also surprising considering even a few weeks ago Professor Swinburn was happy to be included in a private Twitter message to me showing him enjoying cupcakes in his University office," said Mr Graham.

He said he would not comment specifically on the contents of the document at this stage.

Swinburn said on Tuesday he could not comment further on the case either and was waiting to hear back from the court, which would review the lodged proceedings within 25 business days.

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