Australia has formally warned the United Nations climate summit in Copenhagen that negotiations to save the planet are not on track.
Delegates from 192 nations in the Danish capital have been trying to work out ways of fighting global warming after the first phase of the Kyoto Protocol expires in 2012.
More than 50 ministers have now arrived at the conference and will take over the process from Sunday. World leaders are due to fly in later in the week to attend a summit on Friday.
At the halfway mark, Australia's climate change ambassador Louise Hand has announced that things are not going well, the AAP reports.
Ms Hand said her country is seriously concerned by existing gulfs on issues that are essential for a deal. "We are currently not on a path to deliver the environmental outcome we need."
Australia is worried about an official UN draft treaty, which would force rich countries to cut emissions quickly while being more lenient on developing countries such as China.
Australia's Climate Change Minister Penny Wong, who is in Copenhagen, reiterated on Saturday that the draft "isn't good enough" and called on politicians to step in and save the talks.
Senator Wong said the big problems in the talks were the targets to cut greenhouse gas emissions, how to verify that countries made good on their climate promises, and how to finance poorer countries to tackle global warming.
The BBC reports documents prepared by the conference's leaders call on developed nations to cut greenhouse gas emissions by between 25% and 45% of 1990 levels by 2020.
The exact target for limiting temperature rise is unclear amid disputes between various blocs. Small island states want temperature rises held to less than 1.5 degrees celsius, but nations including the US want the limit to be 2 degrees celsius.
Hundreds detained during rally
The conference has also been the scene of a mass demonstration, attended by tens of thousands of people on Saturday.
Police say about 30,000 people marched through the city to where the conference is being held, but protest groups put the number as high as 100,000.
A police spokesman said just four or five out of 968 who were detained would be charged and appear in court.
The move came after youths threw bricks and smashed windows as demonstrators marched to demand action on global warming.
Police say four cars were set on fire elsewhere in the city and one officer was hurt by a stone.
Security was tight along the 6km route, with extra police on the streets and security fences put up around some buildings.
Marches were also held in Australia, Hong Kong, Jakarta and the Philippines.