Amazon Marketplace now handles half of all sales on its websites globally, the company said in a posting on its Australian website.
The Australian operation would be the US giant's fourth Amazon Marketplace in Asia after China, Japan and India and its 12th globally.
Amazon is expanding Down Under, opening warehouses that'll enable cheap, fast local shipping, and letting small businesses sell goods through the site-a development an Amazon employee reportedly said would "destroy the retail environment in Australia".
Australians have already been able to use an Australian Kindle store on the Amazon website, which launched in 2012, and there are already nearly 1000 employees in the country.
Other Australian retailers that could suffer include Premier Investments Ltd. (PMV.AU), Super Retail Group Ltd. (SUL.AU) and RCG Corp.
JB Hi-Fi and Harvey Norman have both seen falls in share prices since the roll-out of Amazon began.
"While compliant sellers and electronic distribution platforms will charge GST, non-compliant sellers and electronic distribution platforms will be able to ship parcels to Australia at prices that appear more attractive to the consumer, with low risk of detection", it said in a submission to the parliamentary committee hearing on the proposed tax legislation, which will be held on Friday.
The electronic giant is also expected to sell groceries at its Australian stores through Amazon Fresh, which could take on the major supermarkets, including Coles, Woolworths and Aldi.
The Nielsen survey followed a report last year by Citigroup, which estimated that Amazon could garner 7 per cent of the total electronics market and 33 per cent of online electronics sales within five years worth $1.8 billion.
Amazon would also compete with eBay Inc. Rather than partnering with a single company such as Australia Post, Toll or DHL, if its history in the United Kingdom is any guide it is likely to use multiple large and small providers to ensure fast delivery.
The company started competing with streaming services Netflix and Stan with the recent Australian launch of Amazon Prime Video, bringing Top Gear redux "The Grand Tour" to Aussie fans.
"There are already thousands of Australian businesses selling their products on existing Amazon Marketplaces".