Production down 2 pct to 1.12 million carats

* Closure of Finsch buy expected in coming weeks

* On track to more than double output in 2011/12

* Move to LSE main market planned by end of 2011 (Adds CEO and analyst comment, share price)

LONDON, July 19 (Reuters) - Africa-focused miner Petra Diamonds said full-year revenue rose 24 percent, as higher rough diamond prices and fast-growing demand in Asia outweighed a decline in production.

Revenue rose to $221 million in the year to end-June and would have jumped 55 percent excluding the $35 million sale of the Cullinan Heritage diamond. The gem, included in the company's 2009/10 figures, set a record price for a rough diamond.

Production fell 2 percent to 1.12 million carats and the company, the largest diamond producer on London's junior AIM market, expects output to double in the 2012 financial year mainly on the acquisition of the Finsch mine in South Africa.

Petra expects to produce more than 2 million carats in the current financial year, Chief Executive Johan Dippenaar told Reuters on Tuesday.

The company will provide a more detailed guidance at the time of full-year results in September when it has a clearer idea of when Finsch will start to contribute.

"Although we expect the Finsch mine acquisition to close shortly, every month that it is not on our books the production target will vary by about 100,000 carats," Dippenaar said.

It expects to close the acquisition of Finsch, South Africa's second-largest mine by output, from De Beers in the coming weeks.

Petra's shares were up 2 percent at 0737 GMT, outperforming a British mining index .

Analysts at Canaccord said Petra's revenues exceeded its expectations by 2 percent largely due to the exceptional strength in diamond prices. It had anticipated 30 percent rise in diamond prices in the second half from the year-earlier period whereas actual prices jumped 58 percent on average.

The diamond market has performed strongly in 2011 helped by firm retail demand, particularly from China, India and, to a lesser degree, the United States, Petra said.

"In the absence of any major financial crisis, the outlook remains very solid because supply is so constrained," Dippenaar said.

He added that he has seen some evidence of diamonds being sought as an alternative asset class, in the same way record high gold prices are being boosted by its safe haven status, although he said this was quite small in terms of overall consumption.

Petra also said it is looking to strengthen the board with the appointment of new independent non-executive director as part of its plans to move to the London Stock Exchange's Main Market by the end of 2011.