Impala Platinum, the world's second-largest producer of the precious metal, said on Wednesday its first-half earnings likely increased by up to 65 percent, lifted by stronger sales and higher prices.

The South African miner said headline earnings per share for the six months to end-December likely totalled between 329 cents and 350 cents, up from 212 cents a year earlier.

Headline earnings are the main gauge of profit in South Africa and exclude certain one-time items.

The higher earnings were largely due to increased metal prices and sales, Implats said.

However, the company said earnings were tempered by the strength of the rand. The currency has gained about 26 percent since the start of 2009, a negative for South African miners that sell metals for dollars.

Implats shares, which have fallen about 8 percent so far this year, closed 0.70 percent higher on Wednesday at 214.51 rand, compared with a 1 percent rise in Johannesburg's All-share Index.