Australian Climate Change Minister Penny Wong said on Tuesday the carbon reduction scheme is key to a global agreement to tackle climate change after the government's climate adviser questioned whether the scheme was worth introducing in its current form.

"If (opposition leader Malcolm) Turnbull ... wants to vote this down what it will send is precisely the wrong signal to the global negotiations at precisely the wrong time. It will signal to other countries that Australia's targets have no credibility because we have no plans to meet them," Senator Wong told ABC Television.

Wong has also rejected the suggestion that Australia should not attend an upcoming United States-led forum on energy and climate.

"We do think it's extraordinary that the opposition is so negative that they would seriously be suggesting that it is a bad thing," Senator Wong said.

The government has so far failed to win the support of key cross bench senators for its proposed Emissions Trading Scheme (ETS) in the meeting with U.S.