Government moves to protect the Great Barrier Reef would not have occurred but for green groups “holding governments to account”, Queensland’s environment minister, Steven Miles, says.

The federal environment minister, Greg Hunt, has accused environment groups of exaggerating threats to the reef, citing Greenpeace for waging a “deceptive campaign” to have it declared “in danger” by the UN.

But Miles voiced his support for the role of green groups before his trip to Germany for a final UN decision this week on the reef’s listing.

Miles, the state’s first designated minister for the reef, also defended green groups’ tax status as charities, which is under review by the federal government after mining industry complaints led to a Senate inquiry.

Hunt, who will join Miles to press Australia’s case in Bonn before the world heritage committee ruling, said last month Greenpeace had misled people around the world, including by using photos of storm-ravaged coral in the Philippines to illustrate the potential threat to the reef.

Miles told Guardian Australia environmental groups had been instrumental in forcing a radical shift in conservation efforts that he now expected to result in the committee adopting a draft ruling against an in-danger listing.

“I think we would not have achieved the colossal changes we have, the reef would not have the chance it now has, if it weren’t for the focus of some key environment groups, and of the course the world heritage committee,” he said.

“So I certainly won’t be criticising people, even though there will be times I don’t agree with their assessment, there’ll be times where they’re critical of things I do or initiatives of our government. But I welcome that.

“And I certainly support their ongoing tax status as charities. I think if members of the public, if citizens of Queensland or Australia want to put their hard-earned cash into an organisation that fights to protect our environment, well I think they should be able to tax-deduct it.”

The world heritage committee is expected to make its final decision on Wednesday or Thursday, with Hunt and Miles hoping to get one minute each to address the committee beforehand.

The delegation in Bonn will also include representatives from WWF-Australia. Its chief executive, Dermot O’Gorman, said he retained “serious concerns” about Australia’s long-term conservation plan.

O’Gorman said there was a “strong chance” Unesco would declare the reef in danger if a progress report due in 18 months did not show the Australian government plan, which needed a “significant injection of funds”, was effectively rolled out.

He said the committee would almost certainly declare the reef in danger in 2020 “unless there is a significant improvement” in its condition by then. “In reality Australia is being put on probation,” O’Gorman said.

Some in the federal government who have worked on the reef conservation plan dispute this characterisation of the UN draft ruling, saying the terms “on probation” or the reef being on a “watchlist” are not part of its terms.

Miles said his interpretation was that Unesco had a “watching brief” on a reef plan it approves of but wants to see implemented over two- and five-year timeframes. “I, for one, really welcome that,” he said. “It strengthens my hand as minister to make sure we get on with the job and get it done.

“But clearly there’s an implication that if we’re not, they’ll revisit the question of an in-danger listing.”

Miles said it was impossible to know whether Labor’s late addition to the reef conservation plan after its surprise election victory over the former Newman government had averted a listing. “I think if you look at the decision, though, the key points that they touch on are the commitments that Labor took to the election and have since been implementing.”

The draft UN ruling noted Queensland’s promise to ban the dumping of capital dredged sediment in the reef world heritage area, limit industrial activity at ports and introduce targets to cut 80% of nitrogen and 50% of sediment by 2025.

“My reading of the draft decision is they’re saying, we note the very significant commitments made, then they list the commitments and they’re the key changes that we made to the plan on our election,” Miles said.

“That’s not saying we took all of the credit for it, but I certainly think that we strengthened Australia’s chances.”

Miles said he could not elaborate on discussions with the commonwealth about a funding framework Unesco wants to see implemented this year.

But he said they were working together to “better align our investments” after years of money being misdirected to less effective conservation measures.

“One of the criticisms I had is that we’ve actually spent a lot of money over a lot of years and the [Queensland] auditor general [recently] pointed out it’s been very difficult to tell whether that’s been very effective,” he said.

“That’s a problem. People, taxpayers, will stop supporting us continuing to invest money if we can’t demonstrate success.”

Federal government MP George Christensen on Tuesday took out a two-page “advertorial” in a Mackay newspaper attacking environmental groups for working against the mining industry on the reef while enjoying charity tax status.

The Daily Mercury spread featured the views of the Queensland resources council, senate inquiry chair Alex Hawke, and of Christensen himself in an article titled “Green groups attack jobs ‘on your taxes’”.

Greenpeace chief executive David Ritter said the ads were “fossil fuel industry propaganda [that] reveals for all to see the unhealthy cosiness of the Abbott government” and the mining lobby.