Climate change is a hoax developed as part of a secret plot by the United Nations to undermine democracies and takeover the world, a top adviser to Tony Abbott, Australia's prime minister, has warned.

Maurice Newman, the chief business adviser to the prime minister, said the science showing links between human activity and the warming climate was wrong but was being used as a "hook" by the UN to expand its global control.

"This is not about facts or logic. It's about a new world order under the control of the UN," he wrote in The Australian.

"It is opposed to capitalism and freedom and has made environmental catastrophism a household topic to achieve its objective." Born in Ilford, England, and educated in Australia, Mr Newman, a staunch conservative and former chairman of the Australian Stock Exchange, has long been an outspoken critic of climate change science.