Mining behemoth BHP on Wednesday sought a deadline extension in its takeover pursuit of Anglo American, outlining a suite of measures to soothe shareholder concerns that have derailed previous offers.

A core part of BHP's plan is splitting off of Anglo's platinum holdings in South Africa, a politically sensitive move that has stirred government opposition ahead of the country's general election Wednesday.

South Africa's state investment vehicle wields significant influence as one of the largest shareholders in Anglo American.

BHP outlined a set of measures aimed at mollifying these concerns, including a commitment to maintain current employment levels at Anglo's Johannesburg office.

"BHP believes that the proposed measures it has put forward provide substantial risk protection for Anglo American shareholders," the company said in a statement to the Australian stock exchange.

"BHP believes a further extension of the deadline is required to allow for further engagement on its proposal," it added.

Under UK takeover rules, BHP has until May 29 to stitch together a deal, request an extension or walk away.

Any deal between two of the world's largest resources companies would fundamentally reshape the sector, with far-reaching consequences for commodities markets and the global energy transition.

BHP earlier this month made a bid of US$43 billion, which would rank as one of the largest mining deals ever seen.