(REUTERS) -- Impala Platinum, the world's second largest platinum producer, said on Friday the Zimbabwean government had rejected part of an empowerment plan submitted by its unit Zimplats.

A heavily criticised law mandates that all foreign miners sell a 51 percent stake to local Zimbabweans. Implats said the government had rejected a proposal that credits be given for mining claims Zimplats had ceded in a 2006 deal with the Zimbabwean government.

Separately, Zimbabwe has also rejected a local ownership plan submitted by Mimosa Holdings, a 50-50 joint venture between Aquarius Platinum and Implats, the two miners said earlier on Friday, fuelling uncertainty about the future of the venture.