Australia's original climate change-focused think-tank and lobby group will shut after it failed to replace the multi-million-dollar bequest it relied on.

The Climate Institute, known for its research and leading role in public debate since being set up in 2005, will close in June.

It comes 18 months after the institute called for public donations to offset the lapsing of the foundational support set up by Rupert Murdoch's niece, Eve Kantor, and her husband, farmer Mark Wootton.

Mr Wootton, also the institute's chairman, said he was proud that the institute had built understanding of a complex issue during a tumultuous time in Australian public life.