Australian mining giant BHP announced on Monday that British rival Anglo American has rejected an "improved" takeover bid worth £34 billion (almost HK$333.5 billion).

BHP's latest offer, which aims to create the world's biggest-listed copper producer, comes after its initial £31.1-billion approach had already been rebuffed last month.

"The revised proposal was rejected by the Anglo American board on 13 May 2024. BHP is disappointed that the... board has chosen not to engage with BHP with respect to the revised proposal and the improved terms," the company said in a statement.

The new bid was pitched at £27.53 per share, up from £25.08 per share that had been slammed by Anglo as "highly unattractive" and "opportunistic" in April.

BHP has lifted the number of shares that would be given to Anglo investors under the improved terms.

And it still plans to split off Anglo's platinum and iron ore subsidiaries in South Africa, with shares split between the British firm's shareholders.

"BHP put forward a revised proposal to the Anglo American Board that we strongly believe would be a win-win for BHP and Anglo American shareholders," said BHP chief executive Mike Henry.

"We are disappointed that this second proposal has been rejected," he added.

The latest offer would increase Anglo's share of the new combined group to 16.6 percent, up from 14.8 percent previously.

"BHP and Anglo American are a strategic fit and the combination is a unique and compelling opportunity to unlock significant synergies by bringing together two highly complementary, world class businesses," added Henry.

"The combined business would have a leading portfolio of high-quality assets in copper, potash, iron ore and metallurgical coal and BHP would bring its track record of operational excellence to maximise returns from these high-quality assets."

In mid-afternoon deals on the London stock market, Anglo American's share price slid 0.8 percent to £27.51, while BHP dipped 0.6 percent to £22.83. (AFP)