Miner BHP Billiton Plc/Ltd is due to file with Chinese competition authorities later in June for its planned $170 billion takeover of Rio Tinto Plc/Ltd, the company said on Wednesday.

We'll be filing with regulators in China later this month, London spokesman Illtud Harri said.

The world's biggest mining group planned to file in Japan, Taiwan and Korea at a later date, he added.

BHP has said it expects a long review process by regulators and Harri said the company has already filed with competition authorities in Europe, the United States, Australia, Canada and Australia.

Chinese companies and officials have opposed a combination of Rio and BHP, the world's second and third biggest iron ore producers respectively, fearing the merged group would have too much pricing clout in the raw material for steelmaking.

China, the world's largest steelmaker, consumes around half of the world's iron ore production each year.

Analysts say a combined group would control about 35 percent of the global seaborne traded iron ore market, while BHP uses a different calculation, putting the share at 27 percent of the world's contestable iron ore market.

A new anti-monopoly law is due to take effect in China on Aug. 1 but experts said some aspects of the law and its application were still unclear.

Authorities will review any transaction involving companies with a combined Chinese market share of 25 percent, they said.

Under the law, transactions would also have to be notified in which two companies each have sales of more than 300 million yuan in China and jointly have Chinese sales of 1.7 billion yuan or global sales of 9 billion yuan ($1.3 billion). (Additional reporting by Tom Miles in Hong Kong and Lucy Hornby in Beijing; Editing by David Holmes) (Reporting by Eric Onstad; Editing by David Holmes)

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