Australia's competition regulator said on Friday that BHP Billiton Ltd
The Australian Competition and Consumer Commission said it will invite comment from other participants in the mining industry, their customers and other interested parties.
Information on the main issues that the ACCC will be addressing will be available early next week on the ACCC's Web site, www.accc.gov.au, it said.
It did not give a timeframe for the review.
Rio Tinto has spurned BHP's all-share offer, which is currently worth more than $180 billion. The bid has sparked opposition from steel companies around the world over concerns that a merged entity would have too much control over pricing of raw materials such as iron ore.
Last week BHP filed with the European Commission for clearance to take over Rio, and said recently that it expected that review to go to a second phase.
Analysts say the most contentious area is likely to be iron ore, since the combined firm would control around a third of seaborne trade in the raw material for making steel.
The Commission, the European Union's executive arm and also its antitrust regulator, set a deadline of July 4 for consideration of the deal.
By that date it must either approve the deal on competition grounds, open an in-depth investigation, or permit a short extension.
The deal must also pass regulators in the United States, Canada and South Africa. (Reporting by Jonathan Standing)
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