Most climate models were wrong and there was little evidence of climate change, said Maurice Newman.
He said the UN had used climate change as a “hook” to establish and control a new world order.
Mr Newman’s comments were rejected by climate scientists, while Environment Minister Greg Hunt said it was “not something I would express”.
Asked at a press conference what he thought of Mr Newman’s comments, Mr Hunt said individuals were “entitled to their views”.
On a per capita basis, Australia is one of the world’s biggest emitters of greenhouse gases.
Coalition governments in Australia have a history of climate change scepticism. One of the current government’s first actions when it won power in 2013 was to dump the previous Labor government’s tax on carbon emissions because of the cost to industry.