Mumbai: Australian Competition and Consumer Commission (ACCC) has commenced its review of the proposed acquisition of Rio Tinto by BHP Billiton after the watchdog received a buy-out plan of about US$170 billion (A$178 billion).

ACCC has received a submission from BHP Billiton about its plan to buy rival Rio Tinto for about A$178 billion, the commission said in a statement sent to the Australian stock exchange.

BHP Billiton, the world's largest mining company, is offering 3.4 shares for every Rio Tinto share, valuing the deal at about US$170 billion (A$178 billion).

BHP Billiton  last week filed its first submission with the European Commission, the European Union's antitrust regulator, on the proposed takeover of London-based Rio Tinto.

The European Commission has between 25 and 35 working days to approve the deal after receiving the submission, or extend it to five months  and  consider the takeover in greater detail.

Melbourne, Australia-based BHP has greater influence over global iron-ore prices. An alliance with Rio would give it a third of the world's traded iron ore and make it the biggest producer of power-station coal and the second-largest producer of aluminum.

ACCC is seeking public comments from the mining industry, customers and other interested parties on the proposed merger. Written submissions should be submitted by July 1.

While BHP Billiton may have to dispose some assets for the takeover to succeed, particularly iron ore assets, it will still leave the miner with much clout. Steelmakers have expressed concern about reduced competition and stronger pricing control by a merged group.

Besides BHP has filed documents with regulators in South Africa and the United States.

The offer is also subject approval from the Foreign Investment Review Board in Australia. BHP may need to file 100 regulatory applications, Kloppers said in February.