Under the accord struck at last month's Copenhagen climate change summit, developed nations are required to submit their emissions reduction targets to the United Nations by January 31.

According to The Australian Financial Review, this suggests the government has just three weeks to decide what Australia's 2020 commitment should be from within an emissions target band that ranges between a 5 per cent and a 25 per cent cut below 2000 levels.

But it would have to do so without knowing the answer to crucial questions about how Australia would measure its emissions, particularly in the agriculture, land use and forestry sectors, which have a major bearing on Australia's overall carbon footprint.

Although the carbon accounting rules regarding land use and forestry were supposed to have been finalised at Copenhagen, the slow pace of negotiations means these issues remain unresolved.