South Africa-focused Petra Diamonds said it expected production in the year ending next June to grow by about 30%, helped by contribution from its Finsch and Williamson mines and higher output at its Kimberley Underground mines.

The diamond miner said profit from mining activity rose 35% to $103.3m in the year ended June 30. Production nearly doubled, mainly due to the contribution from Finsch - South Africa's second-biggest diamond operation.

Petra, which has interests in seven operating mines in South Africa and one in Tanzania, expects to produce 2.85 million carats in fiscal 2013.

Its plans to ramp up production to 5 million carats by fiscal 2019 were on target, the company said. Shares in the company closed at 109.7 pence on the London Stock Exchange on Friday.