Sydney  - The Australian government's hopes of taking a carbon-emissions trading plan to December's climate change conference in Copenhagen were dashed Thursday when enabling legislation was blocked in parliament.

The opposition Liberal Party, which is stacked with climate change sceptics, voted against the bill because it said it was worried over the loss of jobs.

The Greens also helped veto the bill, saying Prime Minister Kevin Rudd's pledge of a unilateral reduction in emissions on 2000 levels of 5 per cent by 2020 is derisory.

Rudd argues that lifting the target above 5 per cent would be possible if other countries, including developing countries, also set targets in that range at the Copenhagen meeting.

Climate Change Minister Penny Wong said she would re-introduce the scheme to parliament later this year.

"Whilst those on the other side want to continue to deny that climate change is real and continue to be divided on this issue, we are firm in our resolve to do the right thing," she said.

Liberal leader Malcolm Turnbull said more support for coal mining firms and a greater capacity to reward the storing of carbon in soil and trees could tempt the opposition into allowing the bill to pass when it is introduced.

Australia is among the world's biggest polluters on a per capita basis, with emissions per head at least five times China's. It's the world's largest exporter of coal, the emissions-rich non-renewable source it relies on for over 80 per cent of power generation. (dpa)