ABC

Crossbench Senators say they are not impressed by Prime Minister Kevin Rudd's attack on those who oppose his climate change policy.

Mr Rudd on Friday launched an invective towards climate change deniers and said it was political cowardice to delay passing the emissions trading scheme until after talks in Copenhagen.

"The clock is ticking for the planet, but the climate change sceptics simply do not care," he said.

But Family First Senator Steve Fielding disagrees, saying it is economically reckless to do anything before Copenhagen.

"[It's] another one of Kevin Rudd's hissy fits and he's in a mode of panic," he said.

Mr Rudd also attacked so-called climate change sceptics who he says are holding the world to ransom.

Greens leader Bob Brown, however, says that is hypocritical and if Mr Rudd was serious acting on climate change, he should push for bigger cuts to emissions.

"The emperor's got no clothes. He himself is captured by the people in the sceptics' camp," he said.

Meanwhile, Independent Senator Nick Xenophon also says Mr Rudd should put forward bigger cuts and release Treasury modelling on variations to the scheme.

Negotiations over changes to the scheme are continuing between the Government and Opposition and it will go to the Senate for a vote in the final parliamentary sitting week of the year.

Climate Change Minister Penny Wong has confirmed the Government could not accept all of the Coalition's proposed amendments due to budgetary constraints.