The business leaders of 140 global companies are calling for deep and rapid cuts in greenhouse gas emissions to come from a United Nations climate change summit, but the Australian Government is playing down expectations that these talks will lead to action.

Climate Change Minister Penny Wong is scheduled to fly to Poland today to join the summit in the Polish city of Poznan.

She said yesterday the summit would not involve specific targets, rather it would ''set the stage for a much more intensive set of negotiations next year'' in Copenhagen.

''I think it is an enormously difficult task and it's an enormous challenge,'' she said.

''I don't think we can underestimate the effect of the global financial crisis on this policy area ... it's an extraordinarily difficult times in terms of the world's financial system.''

Greens senator Christine Milne accused the Government of using ''Howard-era negotiating tactics'', saying its refusal to commit to a minimum negotiating range of 25-40per cent emissions cuts by 2020 was seen as a block to a successful outcome in Poland.

It is understood the Government is considering a target range of 5-15per cent. However, the Government has refused to reveal its medium-term goals until mid-December when it plans to issue a white paper on its proposed emissions trading scheme, despite earlier promising to outline its goals before this UN summit.

The Australian Conservation Foundation is also pushing for a 25-40per cent cut and issued polling it commissioned to back up its claims yesterday.

Almost two-thirds of 1000 respondents want Australia to set an example by committing to strong targets to reduce carbon pollution, it found. Less than a third thought Australia should only commit to strong targets if other major countries agreed.

The group of global companies including Westpac, National Australia Bank, transport giant Linfox, PricewaterhouseCoopers, Lend Lease, Mirvac and Insurance Australia Group will issue a communique today calling for ''transformational change'' of the global economy and ''deep and rapid cuts in greenhouse gas emissions''.

The group has rejected arguments the global downturn is reason to tread softly, saying decisive action now will stimulate economic activity.

It wants developed countries to take on immediate and deep emission-reduction commitments, and cuts of 50-85 per cent of greenhouse gases by 2050, saying delaying action would increase the costs of stabilising the climate.

The group of companies proposes a series of linked national or regional cap-and-trade systems, non-price interventions such as regulations and performance standards, and more assistance for poor countries.

Ms Wong said Australia recognised its obligations as a developed nation to cut carbon pollution.

''We also know that to get what we all want and what Australia needs that is, an effective global agreement we need the cooperation and involvement of all the major emitters,'' she said.

Australia would play its ''full and fair part ... at the lowest cost to the economy''. with AAP