The respected economist and former Labor adviser Ross Garnaut has delivered a scathing critique of the political and economic records of the major two parties, accusing both of a failure of leadership over the past decade.

Neither party had a plan to deal with climate change and Australia's position on the issue was ''an extraordinary failure of leadership''.

Professor Garnaut said Kevin Rudd abdicated leadership by listening to advisers who rated lobbying by special interest groups and ''inchoate reactions'' from poorly informed members of the community above majority public support for action.

Ms Gillard was now accepting similar advice, he said, and may be on a similar path.

On the international stage, Australia's bipartisan minimum target of a 5 per cent cut in greenhouse gas emissions below 2000 levels by 2020 stood out for its weakness.

''Worst of all, neither of the major political parties has committed itself to policies that can get us anywhere near the unconditional commitment to a 5 per cent reduction,'' Professor Garnaut said.

Ross Garnaut denounces failure of leadership