Former Liberal leader Dr John Hewson says the Federal Government should abandon its bid to scale back the renewable energy target, calling it a political barnacle that needs to be removed.

The RET aim is for Australia to generate 20 per cent of electricity from renewable sources by 2020, a target of 41,000 gigawatt hours.

But the government wants to slash the target to 27,000 gigawatt hours, in response to falling electricity usage.

Prime Minister Tony Abbott told a coalition joint party meeting last week he is aiming to scrape off "one or two barnacles" before the Christmas break.

Dr Hewson, who is also an economist, said that the target needs to be maintained.

"If you're talking about barnacles, get rid of this one," he argued.

"He had a pre-election commitment to keep it ... It costs him nothing to leave it there. It has no impact on the budget."

Dr Hewson said the Abbott government is off the pace of worldwide climate change developments.

The Minister for Industry Ian Macfarlane responded in a statement, and said the renewable energy industry is facing uncertainty because the RET is not operating the way it was intended.

"Uncertainty has existed for a number of years and many in the renewable sector privately acknowledge the current target is neither sustainable nor achievable," he replied.

"The Government wants to fix the problems that are hindering investment under the current RET to ensure renewables can be a sustainable part of our energy mix."

The Clean Energy Council's Kane Thorton said investment in the sector has been stifled and tens of thousands of jobs are now in jeopardy.

According to the International Energy Agency, worldwide investment in renewable energy needs to increase four-fold to $1 trillion in order to meet international climate change targets by 2030.