(REUTERS) -- Impala Platinum, the world's second-biggest platinum producer, has made an irrevocable offer to hand over a 29.5 percent stake in its Zimplats unit to a state-run fund, a senior Zimbabwe minister said on Wednesday.

Harare has been pushing Implats to hand over majority control of Zimplats to local investors under a new 'black empowerment' law. Implats has been digging in its heels, especially over the latest demand for a stake worth more than $300 million.

They wrote to us today making an irrevocable offer to comply and seeking an extension of the deadline to Tuesday to allow the Implats board to meet this Friday, Empowerment minister Saviour Kasukuwere told Reuters.

We have accepted that.