LONDON (Reuters) - Activist investor Elliott Advisors on Monday stepped up calls for the world's biggest mining company BHP (>> BHP Billiton Plc) (>> BHP Billiton Limited) to scrap its dual listing, demanding the company agree to review the matter by the time it posts results on Feb. 20.

Elliott has previously urged BHP to change its structure, with listings in both Britain and Australia, but the company has resisted.

BHP declined to comment on Elliott's latest letter to its board, in which the activist investor said that removal of the dual-listing structure would deliver more than $22 billion of shareholder value, citing its own independent report.

"The report highlights the next necessary step at BHP, which is for the board to commit to resolving the issue of BHP’s obsolete and value-destroying dual-listed company (DLC) structure," Elliott said in a statement.

Elliott, which holds a 5 percent stake in BHP, demanded that the company agree by Feb. 20 to undertake "a full, independent and transparent review" of the proposal.

BHP has been under attack since Elliott went public in April 2017 with criticisms of the miner's strategy. Last October the company's new chairman threw his weight behind CEO Andrew Mackenzie.

Elliott, founded by billionaire Paul Singer, has also been pushing for BHP to jettison its U.S. oil and gas assets after an ill-fated $20 billion investment in U.S. shale.

(Reporting by Eric Onstad; Editing by David Goodman)

Stocks treated in this article : BHP Billiton Plc, BHP Billiton Limited