Australia's climate policies have come under the microscope at a United Nations conference in Germany, with countries asking senior diplomats if the emissions reduction targets are ambitious enough.
The United Nations Multilateral Assessment process aims to transparently compare the emissions reduction efforts of developed nations.
Currently, Australia's 2020 target is a 5 per cent reduction on greenhouse gas emissions from 2000 levels.
The United States wanted to know if the Government's flagship Direct Action policy — which involves paying emitters not to pollute — would get Australia to its 2020 targets.
"Countries are very interested in knowing whether the Emissions Reduction Fund will result in mitigation comparable total in size to the [Emissions Trading Scheme] in which it replaced," the US delegation asked.
"Can you share with us some additional details [on] how Australia ensures the mitigation results of this policy are sufficiently large to achieve your objectives?"
The Department of Foreign Affairs and Trade's Peter Woolcott said the Government's first ERF auction had been successful, but did not give any specifics as to how much carbon the fund was predicted to purchase by 2020.
"We are fully convinced as a government that we will meet our 2020 targets," Mr Woolcott said.
"We now have the legislation in place which will allow us to do so."
South Africa and China questioned whether Australia's target was fair.
"We're reviewing that target currently," Mr Woolcott told them.
"I'd just make the point that this is a fair and equitable target. It's comparable to other major developed countries in OECD."
Australia not open enough: The Climate Institute
The Government reiterated its commitment to consider increasing the target to 15 per cent or 25 per cent, depending on what the rest of the world does.
China pushed the point, seeking to find out when that decision might be made, but Mr Woolcott said the Government's main focus was on emissions cuts for beyond 2020.
"We're earnest about the way we go about setting our targets," he said.
"There's no sense of a stab in the dark — a huge amount of work is going into what is required, what other states have done, what are the domestic ramifications of a target.
"All this work is being done, there's an extensive stakeholder process.
"So the focus is very much on post 2020 targets, but at the same item the conditional aspects for the 2020 pledge remains under consideration."
The Climate Institute's Erwin Jackson said Australia was not open enough and despite questioning made no mention of the cut to the renewable energy target (RET).
Australia only referred to the "amending" of the large-scale RET, which is being cut from 41,000 gigawatt hours to 33,000 GWh.
"Other nations like the United States, China are highly sceptical of Australia's domestic policy framework and Australia's really failed to demonstrate to the international community how its domestic policies are credible and to help us play our fair part," Mr Jackson said.
Germany's meeting follows up on a range of written questions submitted in April.
Australia was asked 36 written questions — the most of any nation — but the questions posed in person overnight were not as critical.
"This is a diplomatic forum, there's always going to be a bit of diplomatic nuance and repartee," Mr Jackson said.
Australia is expected to announce its post-2020 targets in July, which will be negotiated at a global climate meeting in Paris in December.
In April, the ABC revealed the French government urged Australia to take a strong and ambitious position to the Paris meeting.
The independent statutory agency the Climate Change Authority (CCA) has recommended aggressive cuts — 30 per cent by 2025 based on Australia's emissions from the year 2000.