In September 1912 Australia adopted an amended coat of arms.
From Wikipedia:
The escutcheon is the focal point of the coat of arms, contained within is the badge of each Australian state, the whole surrounded by an ermine border representing the federation of the states.
In the top half, from left to right, the states represented are: New South Wales, Victoria and Queensland. In the bottom half, from left to right: South Australia, Western Australia, and Tasmania. Above the shield is the seven-pointed Commonwealth Star or Star of Federation above a blue and gold wreath, forming the crest. Six of the points on the star represent the original six states, while the seventh point represents the combined territories and any future states of Australia. In its entirety the shield represents the federation of Australia.
The Red Kangaroo and Emu that support the shield have never been designated as official animal emblems of the nation. They owe their unofficial recognition to the fact that they are native Australian fauna (found only on that continent), and likely chosen because they are the most well-known native Australian animals large enough to be positioned together in scale holding up the shield. They were chosen to symbolise a nation moving forward, based on the fact that neither animal can move backwards easily – i.e. symbolising progress. It has been claimed that the kangaroo is, and must be seen to be, male.
In the background is wreath of Golden Wattle, the official national floral emblem, though the representation of the species is not botanically accurate. At the bottom of the coat of arms is a scroll that contains the name of the nation. Neither the wreath of wattle nor the scroll are technically part of the design, because they are not described on the Royal Warrant that grants the armorial design.