Greens denied right to campaign: Di Natale

The Greens are taking aim at "the Coles and Woolworths duopoly" of Labor and the coalition after being snubbed from Friday's leaders debate.

Leader Richard Di Natale on Saturday said the debate denied Australians from hearing an alternative voice to the business-as-usual "establishment politics".

"Fancy a debate that doesn't take on global warming and refugees. Neither of the old parties want to go there," he told reporters at the Greens national conference on Saturday.

"It's selling the Australian community out by not providing an alternative voice, and people were denied a choice in the leader's debate."