The leaders of the Australian and New Zealand Green parties are calling on their respective governments to take action on climate change and inequality at the G20 meeting in Brisbane this weekend - topics that are absent from the agenda of the meeting of the world's richest nations.

"The Prime Ministers of our two countries may not be prepared to talk about the issues that are overwhelming the planet, but the Greens are. So are other world leaders. As the G20 host, Tony Abbott needs to get real," said Australian Greens Leader Christine Milne.

The Australian Greens say Tony Abbott is risking Australia's constructive relationship with the United States by seeking to undo existing climate change policies, refusing to put climate on the G20 agenda and retreating from global action.

"Tony Abbott absolutely has his head in the sand on climate change. It's a national disaster and a global embarrassment as China and the USA get serious about the 2015 treaty," said Greens Leader Christine Milne.