The UN climate negotiations are picking up pace after a sluggish start but an emerging split between developed and developing countries has some warning it could derail talks.
At issue is whether formal discussion of increasing action on climate change before the Paris agreement starts in 2020 should be included on the COP23 conference agenda.
The talks come with a sense of urgency as the impact of climate change is felt in destructive cyclones, floods, fires and droughts around the world and recent reports highlighting the gap between what emissions need to be cut and what countries' efforts to date will achieve.
But developed countries - including Australia - are generally resisting attempts for a formal agenda item examining pre-2020 ambitions, saying there is space elsewhere for such discussion.
Senior European Union official Elina Bardram says this point has been turned into a "misperception that the EU or other countries don't consider pre-2020 action very important" when they in fact do and are acting.
"However, as we do have a full negotiation agenda ... we need to be mindful of where we find the best place to discuss the issue," she told reporters in Bonn on Friday.
"Whether introducing a new COP agenda item is the right way to go about it, that's what we are not entirely convinced about."
AAP understands Australia has a similar position, with worries it's already a tough ask to work fast enough to finalise the Paris agreement rules by next year's COP24 without adding more items.
But Brazil - one of the countries pushing for a formal discussion - is dismayed by this.
Chief negotiator Antonio Marcondes says it's "inexplicable" it can't be added because of an already full menu and warned action could not be delayed until 2020.
"Unless we advance very clearly in the tasks before us, the possibility of meeting the deadlines can be jeopardised," he told reporters.
"We cannot run the risk of repeating Copenhagen when the world failed to agree on action."
WWF's global climate policy manager Fernanda Viana De Carvalho hoped the conference would find a way to have the discussion but also cautioned it was important developing countries not turn it into a finger-pointing exercise.
A key issue for Australia is ensuring double counting of emissions is addressed in mitigation and transparency rules and any market mechanism.
The problem can potentially arise in a few areas, including more than one country counting the same cut to emissions against their target.
Ms Bardram said as far as the EU was concerned, unless double counting was stamped out it could corrupt the whole idea of global emissions trading.
"Any trading system on emissions can only work if there is reliability and confidence on one tonne reduced here being equivalent to a tonne reduced there," she said.
Brazil has also flagged concerns about attempts to add rules to the funds set up to help developing countries finance climate action that could limit access for richer or middle-income nations.
"We are making it very clear ... the dangers, the risks of such moves in how much they could affect the capacity of developing countries to keep their ambitions or raise their ambitions," Mr Marcondes said.