According to Bloomberg, Yeager said in an email to all employees of the petroleum unit that BHP would keep the petroleum business. The email was filed with the US Securities and Exchange Commission.

"These stories are not true," the email reportedly said.

"As a member of the group management committee, I have been actively involved in the development of the proposal, and the sale has not been contemplated as part of this proposal.

"The commitment to BHP Billiton Petroleum from the wider company is strong."

The email reiterated comments made a fortnight ago by BHP chief executive officer Marius Kloppers, who said the company has no plans to sell the oil and gas business.

The petroleum unit made over $3 billion in earnings before interest and tax of $3.014 billion in 2006-07, representing about 15% of the company's total earnings.

BHP Billiton Petroleum also produced 116 million barrels of oil equivalent in this same 12-month period, with output to be further boosted this year by the start-up of projects including the Genghis Khan, Atlantis South, and Neptune oil fields in the Gulf of Mexico, and the Angel and Stybarrow projects in Australia.