Russia's secretive state-owned diamond giant Alrosa revealed its reserves and profits for the first time on Wednesday in its latest attempt to improve transparency ahead of a planned public listing.

The disclosure came as the debt-ridden company -- supplier of about a quarter of the world's diamonds -- seeks to find the billions needed to develop an iron ore field near China to help it diversify operations and secure stable growth.

Alrosa's president said an internal audit showed its diamond reserves at 1.28 billion carats, making the company the world's biggest holder of the precious stones.

"Our estimates give us reason to believe that Russia has the world's largest reserves," the Finmarket news agency quoted company chief Fyodor Andreyev as saying.

"At current extraction rates, the company's reserves will last more than 40 years," Andreyev said.

More than 90 percent of the company is held either by the state or the local government of Sakha -- the diamond-rich region of east Siberia where the firm is based -- while another nine percent is traded over the counter.

A Swedish investment fund said last week that its small Alrosa holding valued the Russian firm at $5.5 billion (3.9 billion euros) but Andreyev previously valued it at double that estimate.

Alrosa hopes to list up to a quarter of its shares late next year to help pay off crushing debt and invest in the Timir deposit south of Sakha.

The plan, however, has been repeatedly delayed because the state still views Alrosa as a strategic asset in which foreign ownership is unwelcome and potentially dangerous.

Analysts were split on whether the company would still go ahead with the public listing now that the diamond market is once again booming.

"The trends we are seeing in India and China are blowing everything away," Andreyev said.

The company has reported little success since first saying it had received interest in joint development from several China steel producers and on analyst said the public offering may be Alrosa's only diversification option.

"The project will require investments worth billions of dollars," Moscow's Trust bank wrote in a research note for the Vedomosti daily.

"It seems the funds from the planned 2012 IPO will be directed there," it said.

The Siberian firm revealed a bleak financial picture that showed a recent improvement in performance after a collapse in sales and profits during the 2008 global economic slump.

Alrosa reported a 2010 net profit of 11.8 billion rubles ($415 million) and short-term debt of 12.9 billion rubles ($455 million).

The diamond producer said its net debt stood at 97.8 billion rubles ($3.5 billion) and was down 13 percent from the previous year.

Analysts attributed the drop to an October eurobond placement that generated $1 billion and said they do not think the company will tap foreign capital markets again this year.

The company's 2010 production figure of 34.3 million carats of diamonds placed it slightly ahead of South Africa's private mining firm De Beers.

The Renaissance Capital investment house said 64 percent of Alrosa's 2010 sales -- which were up 45 percent -- came from exports that fetched far higher prices than diamonds sold on the Russian market.

Alrosa also predicted an extended stretch of higher global prices on top of a 26 percent jump in the first three months of the year.

The company's president said emerging market demand had created a $16 billion diamond market for an annual production base worth about $12 billion.