Government ministers and bureaucrats have spent more than $100,000 visiting and lobbying almost all of the World Heritage Committee to convince them not to declare the Great Barrier Reef in danger.

During Senate estimates, the Deputy Secretary for the Department of Environment, Kimberley Dripps, said 19 of 21 WHC nations had been lobbied during overseas visits.

She said the final two nations would be spoken to shortly.

"There is a visit proposed to Senegal and [it is] proposed that the Algerian delegation will be briefed as part of the usual course of business by the ambassador to UNESCO in Paris," Dr Dripps said.

The department also outlined how much it had paid for each lobbying mission but did not include the Minister's costs as they are held by the Department of Finance.

Date Nations visited Who by Department costs Apr 2015 Lebanon, Turkey and Qatar Ambassador for the Environment Peter Woolcott and Deputy Secretary Kimberley Dripps $16,000 Mar 2015 Japan, Korea and India Environment Minister Greg Hunt and departmental staff $12,307.97 Feb 2015 Jamaica, Colombia, Peru Greg Hunt and departmental staff $25,387.97 Jan-Feb 2015 Portugal, Finland, Poland, Germany Greg Hunt and departmental staff $13,904.91 Jan 2015 Kazakhstan Peter Woolcott Unknown – paid for by Department of Foreign Affairs and Trade Dec 2014 Philippines, Malaysia, Vietnam Greg Hunt and departmental staff $12,063.14 Nov 2014 Japan, Korea Peter Woolcott and Kimberley Dripps $8,397.73 Sep 2014 Serbia, Croatia, Germany (side trip after International Whaling Commission attendance) Greg Hunt and departmental staff $17,088.61

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Dr Dripps said she had "very, very long and broad-ranging discussions" with WHC nations.

"[There were] generation questions around: How is the property protected? How does the long-term sustainability plan work? What is the situation regarding capital dredge disposal prohibition?" she told the Senate committee.

"And many, many questions going to down multiple, different technical alleyways in terms of how does a best management program for sugar actually work."

'Whole-of-government' lobbying effort

In Senate estimates earlier this year, Peter Varghese, the Secretary of the Department of Foreign Affairs, said there was a "whole-of-government" effort to prevent the reef being placed on the in-danger list.

"We are running a major campaign to prevent a listing of the Great Barrier Reef as being in danger," he said.

"There have been a number of assertions made about the management of the Great Barrier Reef and about its vulnerability that are not grounded in fact and which need to be rebutted.

"We have tasked several of our heads of mission ... to make that clear to the investment community."

Environment Minister Greg Hunt's whistle-stop European visit in September 2014 cost $41,000 for himself and his chief of staff.

Three-quarters of the cost was spent on attending the International Whaling Commission conference in Serbia.

A draft decision from UNESCO about whether to place the reef in danger is expected to be released at the end of the month, before a final decision is made in June.

Focus should not be on overseas trips: Greens

Greens senator Larissa Waters said the reef needed action, not lobbying trips.

"To save the reef and avoid an in-danger listing, the Minister should be focusing his and the department's attention on following the World Heritage Committee's recommendations, rather than focusing on [overseas] trips," Senator Waters said.

Mr Hunt said the Government had addressed every concern raised by the World Heritage Committee.

"We make absolutely no apology for defending the reputation of Australia's great natural icon on the world stage," he said.

"It would be irresponsible and negligent not to back our strong action with a focus on protecting the reputation of this great icon.

"Along with Queensland, we're investing over $2 billion over the next decade to protect the reef."