"We will examine whether platforms are exercising market power in commercial dealings to the detriment of consumers, media content creators and advertisers", Australian Competition and Consumer Commission (ACCC) Chairman Rod Sims said in a statement.
"Through our inquiry, the ACCC will look closely at the impact of digital platforms on the level of choice and quality of news and content being produced by Australian journalists".
Mr Sims "will have the power to obtain information during the inquiry which will make digital platforms more transparent and enable the ACCC to test whether a case can be made for further intervention or use of the ACCC's broader enforcement powers".
The government ordered the inquiry as part of wider media reforms.
By 2017, analysis was showing that internet advertising, now at 52 per cent of total ad spend, was projected to increase to 65 per cent by 2021.
In the USA, lawmakers grilled Facebook, Google and Twitter last month over how foreign nationals used social media platforms to spread misinformation during the 2016 presidential election.
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He has said to several people, the report added, that he would blame Democrats for a government shutdown. White House Legislative Affairs Director Marc Short , however, denied that Mr.
Australia, one of the most developed economies in the world, is now cracking down on Facebook, Google, Twitter and other networks that disseminate news and influence public opinion.
The inquiry is a response to growing concerns that Facebook, Google and other digital platforms are affecting traditional media providers ability to invest and fund the development of content.
A preliminary report will be delivered in December 2018, with a full report expected in June of 2019.
It is looking for submissions from content creators, mainstream media outlets and smaller operators, platform providers, advertisers, journalists, consumers and small business interest groups.
Media-buying agency GroupM expects Facebook and Google to consolidate their domination of online advertising, and control almost 85 per cent of all online advertising - outside China - this financial year.
While the federal government's announcement of the inquiry didn't mention Google or Facebook by name, it's believed that they will be the main focus of discussions.
"We look forward to engaging with this process as relevant", a Google spokesman told Reuters. Google, however, refused to divulge its market share in Australia.