Implats miners
Implats miners at Rustenberg Mine in South Africa Siphiwe Sibeko/Reuters

(REUTERS) -- A war of words between South Africa's Impala Platinum and Zimbabwe intensified on Thursday, when the world's second-biggest platinum producer denied offering to hand over a stake in its local unit to the government.

A senior Zimbabwean minister told Reuters on Wednesday Implats had agreed to cede the 29.5 percent stake in Zimplats under a new law to transfer majority ownership of foreign companies to local blacks.

Implats said this was not the case.

Implats has not made an irrevocable offer to the Zimbabwe government today, the company said in a two-sentence statement.

Implats has argued that the stake, worth more than $300 million, need not be handed over because it was promised 'empowerment credits' for mining rights it returned to the Zimbabwean government in 2006.

Senior Implats executive Johan Theron said that as far he was aware no letter had been sent to Harare, but the Implats board would meet on Friday to discuss the issue.

A range of options will be put to the board, he said, adding that Implats remained committed to finding a solution to the problem.

Implats shares have fallen 3.3 percent since February 22 when Zimbabwe issued the company with an ultimatum over the Zimplats stake. Rival Anglo American Platinum has dropped 1.9 percent over the same period.