"It's a challenge to Tony Abbott, and how he chose to use language and represent Australia in the world. You have to think very carefully about the words you use when speaking on the international stage," she said.

"And I don't think that was the correct use of language. Putin does need to be challenged but that's not the correct, grown-up way to do it."

Ms Stager also says there's no doubt the Russian president has some serious questions to answer over the shooting down of flight MH17.

And Putin must be held to account too over his government's attacks on free speech, typified by the jailing of members of the anti-Putin Russian punk band Pussy Riot.

She hopes her t-shirts will be everywhere on what she's dubbed Shirt Front Friday, ahead of the official start to the G20 summit of world leaders on Saturday. But anyone who wants one had better be quick.