BHP Billiton said that investors are sitting on the sidelines as they waited for BHP Billiton to overcome regulatory hurdles in its hostile takeover of rival Rio Tinto.

Mr Marius Kloppers CEO of BHPB in an interview aired on Australia's ABC Television said that while he believed that the bid of 3.4 BHP shares for every Rio Tinto share is attractive, it is still up to shareholders to determine whether it went ahead.

Mr Kloppers acknowledged that the ratio of the value of Rio Tinto shares to BHP Billiton shares this month fell to under three for the first time since the bid was launched. He said that this could be linked to the strong performance of BHP but said some investors were waiting for the outcome of regulatory rulings.

He said that "I think it's a combination of how our commodities versus Rio's commodities have developed. And I think it is fair to say that investors are still waiting, sitting on the sideline a little bit, to see how we clear our regulatory pre conditions on this deal."

Mr Kloppers refused to comment on whether the deal would go ahead without the merger of the two companies' iron ore businesses. He said that "It is very hard to speculate on things that we don't think are going to happen and that are not the base line that we are planning around.”

Rio Tinto has repeatedly rejected the BHP Billiton bid, saying it greatly undervalues the company as both firms enjoy huge demand for their raw materials from Asia.