Subsidies for coal-fired power production almost tripled in the three years to 2016-17 among G20 nations, with Australia providing among the largest support, an international study has found.

The report by UK think tank, the Overseas Development Institute, found aid for such power stations soared from US$17.2 billion ($24.7 billion) in 2013-14 to $US47 billion in the most recent year. It's in contrast to pledges made by the 20 biggest economies in 2009 to phase out subsidies to reduce the risks of climate change.

Total support for coal, including production, was US$63.9 billion in the 2016-17 year, the report found. Of that, about US$3.1 billion went to fiscal aid for communities to transition off coal.

The highest amounts of total support to coal consumption were identified in Indonesia at US$2.3 billion per year, Italy and Australia, both about US$870 million, the US at US$708 million, and the UK with US$682 million, it reported.