A tour operator in Cairns has refused to take Greens senators to view coral bleaching on the Great Barrier Reef because negative publicity would be detrimental to the local tourism industry.

Key points: Charter boat operator Daniel McCarthy says "outlandish claims" are hurting reef tourism

Charter boat operator Daniel McCarthy says "outlandish claims" are hurting reef tourism He says Attenborough's "grave danger" comment has been blown out of proportion

He says Attenborough's "grave danger" comment has been blown out of proportion Scientists don't have a political agenda, Greens senator says

Greens leader Richard Di Natale and senator Larissa Waters announced a suite of election policies on Thursday in Cairns that were aimed at protecting the reef, including a transition away from fossil fuels.

The president of the Cairns Professional Fishing Association and local charter boat operator, Daniel McCarthy, told 612 ABC Brisbane he had been asked to take the Greens senators and a scientist to specifically see areas where the reef had been bleached.

Mr McCarthy said the Greens' visit would inadvertently create bad publicity for the tourism sector.

"I made if perfectly clear that I wouldn't have any part of a day on the reef that was going to further build this bloody hysteria story that the reef is dead and all these outlandish claims that is doing a massive amount of damage to the reef's reputation and to the tourism industry's reputation around the globe," he said.

"That reputation is often fed by — whether it's by the Greens, or normally by … these radical green groups around the country … that have no qualms about at all about fudging the truth to a great extent and they don't care who gets hurt on the way."

Mr McCarthy, who is also a former Senate candidate for the Australian Fishing and Lifestyle Party, said the reality was although there was some bleaching on some reefs, most of that was coming back.

"I've been here for 30 years — we've lived through plenty of these types of things, where it's a cyclone that's denigrated the reef apparently — the media's picture of it is 'the world's ending, the reef's gone'," he said.

"If we believed all that — the reef's gone so many times over it's not funny … but it's generally not true.

"Here in north Queensland, our regional economy suffers severely because of the negative press and that is a major problem and that is what we need to stop.

"It was on that basis I refused to take them [the Greens senators] out — I'm not going to feed into that agenda."

Attenborough 'grave danger' comment 'blown out of proportion'

Mr McCarthy said a comment by Sir David Attenborough in a recent BBC documentary that the reef was in "grave danger" had been blown out of proportion by the "negative press".

"People will pick up on one line and they will run away with it and blow it out of proportion," he said.

What is coral bleaching? Occurs when abnormal environmental conditions cause coral to expel tiny photosynthetic algae, called zooxanthellae

Occurs when abnormal environmental conditions cause coral to expel tiny photosynthetic algae, called zooxanthellae Loss of colourful algae causes coral to turn white and "bleach"

Loss of colourful algae causes coral to turn white and "bleach" Bleached coral can recover if the temperature drops and zooxanthellae are able to recolonise them, otherwise it may die Source: ARC Centre of Excellence

"There are a bunch of scientists who will come out and tell you this stuff — the negative end of that spectrum — is actually false."

Mr McCarthy said over several decades he had witnessed areas that had been wiped out by cyclones, crown-of-thorns starfish and bleaching.

"You go back to those areas in a couple of years' time and they are more amazing then they were before," he said.

"It's like a bushfire going through clearing out the old and letting the new stuff come through.

"It's a living, rejuvenating organism and the scientists will tell you how it has come to be how it is — its layers die off, new layers grow on top — and that's how it builds up."

He said local tourism operators and booking agents were "snowed under" with people saying they wanted to cancel their trips to the region because media reports had made them believe there was no reef left.

However, he said people who had ending up visiting the reef always said it exceeded their expectations and "looked like a postcard".

"Is it 100 per cent perfect, no — and it probably never has been," he said.

"But the reef is in great shape and people need to come and have a look at it themselves."

Scientists don't have an agenda: senator

Coral bleached white in shallow waters off Lizard Island in the Great Barrier Reef ( Supplied: WWF )

Senator Waters said she and Senator Di Natale visited several reef sites with another tour operator on Thursday, with scientist Professor Justin Marshall, the head of CoralWatch, on board.

She said the tour included seeing a mixture of healthy and bleached coral.

"I've met with a lot of them [scientists] in the last few weeks, but until you see it with your own eyes, you can't really fathom what the devastation can be like," she said.

She said Professor Marshall told her the pace of change with recent bleaching had been much faster than previous natural events and he was 100 per cent certain it was due to climate change, fuelled by fossil-fuel burning.

Senator Waters said those with an untrained eye like herself and Mr McCarthy might think the reef was still OK because coral bleaching was not always white, but sometimes coloured yellow or blue.

"When people like David Attenborough are saying it might be gone in decades — that's not a man who is prone to exaggeration — and he has no vested interest in talking up the damage," she said.

"I feel for the tourism operators because the don't want customers to cancel their trips because they think there's nothing left to see, but this problem won't go away by ignoring it."

Senator Waters said some global media coverage on the reef was "disappointing ... in particular news outlets".

"Others have been more faithful to what the science is clearly saying," she said.

"The multitude of scientists who are speaking with one voice are begging the Government do something and you don't help the situation by saying 'nothing to see here, move on'.

"Climate change and the reef should be above politics — the scientists don't have an agenda — they are simply just describing what is happening to our natural world."