Key asked to investigate links between Rich and Whale Oil

Prime Minister John Key is facing pressure to launch yet another inquiry in addition to the investigation into Judith Collins' alleged links to a smear campaign against the former head of the Serious Fraud Office.

Allegations made in Dirty Politics suggest the Food and Grocery Council paid Cameron Slater for stories. Source: 1 NEWS

Some of New Zealand's most senior health professionals have shown ONE News a letter they've written to Mr Key raising concerns about a possible conflict of interest involving the head of the Food and Grocery Council, Katherine Rich.

The letter asks the Prime Minister to investigate the relationship between Ms Rich and Cameron Slater.

Ms Rich, a former National MP, is also on the Health Promotion Agency board.

"The major concern is that there are major conflicts of interest between the commercial interests of the food and alcohol industry and on the other hand of good public poilcy and public interest," says Boyd Swinburne, a University of Auckland Professor.

Allegations in Dirty Politics claim the Food and Grocery Council paid Cameron Slater to post stories on his blog which favoured the council's clients - clients which include liquor and fast food companies.

"If it's found that she has been denigrating public health officials and undermining public poilcy, then of course the obvious action is that she be removed. But it needs to be investigated," Professor Swinburne says.

Labour leader David Cunliffe says he supports that and it would be fully covered by the expanded terms of reference in the inquiry Labour has called for.

Mr Key says he hasn't seen the letter form the health professionals.

"So my office will probably be dealing with that. At the end of the day we could take advice on that."

Ms Rich wouldn't appear on camera for ONE News but rejects claims she has been involved in any campaign to undermine public health and says she finds the very suggestion offensive.

The Food and Grocery Council says it speaks regularly to all types of media, including bloggers.

But it rejects claims it pays for any media coverage and says its involvement with the media is not slanted in any political direction.

Mr Key also laid out out the mechanics for an inquiry into Judith Collins' relationship with former SFO head Adam Feely. It'll be conducted by former High Court judge Lester Chisholm.

"This is a serious, proper, thorough, professional inquiry," Mr Key says. Asked if he will widen the inquiry, he said: "If he comes back and says there are other areas of concern we'll go and look at it."

As it is set out now, the inquiry will look into the questions:

- Did Ms Collins conduct fall short of what's expected of a minister by undermining or attempting to undermine the SFO chief?

- Did she provide information about the SFO chief to blogger Cameron Slater or anyone else who wasn't entitled to such information?

- Did she inappropriately seek or receive information about Adam Feeley?

The inquiry must report back by November 28th.