UPDATE 1-Australia's Newcrest H1 profit slumps, rising debt sparks concern

* Underlying profit fall not as bad as expected

* Net debt rises to $4.5 bln, gearing over 30 pct

* Shares tick lower, down more 50 pct over past year

(Adds CEO, anlayst comments, share price reaction)

MELBOURNE, Feb 14 (Reuters) - Newcrest Mining Ltd NCM.AX , Australia's biggest gold miner, reported a 36 percent drop in first-half underlying profit on Friday, hit by a slump in the gold price that also forced it to cut its estimated reserves and resources.

Newcrest is emerging from a tough 12 months when gold prices plunged 28 percent, it suffered problems at some mines and took $6 billion in writedowns. It is now focused on reining in costs and slowing expansion projects to boost cash flow.

"Overall our focus remains on optimising our current operations, maintaining our growth options and maximising free cash flow to enable the company to reduce gearing and return to paying dividends to shareholders," Chief Executive Greg Robinson said in a statement.

While the underlying result was better than the market had expected, analysts were nervous about a rise in net debt to $4.5 billion, which could force the company to sell new shares to shore up its balance sheet later in the year.

"The market's right to be nervous about a potential rights issue. The half-year (result) hasn't quite put that concern to bed," said David Lennox, an analyst at Fat Prophets in Sydney.

Newcrest shares were down 0.5 percent at A$11.20 in morning trade, and have fallen more than 50 percent over the past year.

Newcrest said it was comfortable with its gearing position and on Thursday said it had no plans to raise equity.

It still aims to achieve positive free cash flow this year, assuming an average gold price of A$1,450 an ounce.

Meeting that assumption could be tough. A Reuters poll of 37 analysts published in January forecast an average gold price of $1,235 per ounce this year. At that price, the Aussie dollar would have to average about 85 U.S. cents to achieve Newcrest's target. The Aussie dollar is now trading above 89 U.S. cents.

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Newcrest's underlying profit slid to A$207 million ($186 million) for the six months to Dec. 31 from A$320 million a year earlier, however that was better than analysts' consensus forecast around A$166 million.

Net profit fell 88 percent to A$40 million, hit by previously flagged research and development tax payments and a A$47 million writedown of its west Africa exploration assets.

It declared no interim dividend, due to the slump in profit and a rise in its gearing level to 30.5 percent from 17 percent a year ago, as net debt climbed.

Newcrest followed top global producer Barrick Gold Corp

ABX.TO in cutting estimates on the reserves and resources it has in the ground, after the drop in bullion prices made lower grades of ore uneconomical to produce.

It cut its ore reserves estimate by 11 percent to 78 milion ounces and its resources estimate by 7 percent to 150 million ounces.

($1 = 1.1133 Australian dollars)

(Reporting by Sonali Paul; Editing by Richard Pullin)

((Sonali.Paul@thomsonreuters.com)(+61 3 9286 1419)(Reuters Messaging: sonali.paul.thomsonreuters.com@reuters.net))

Keywords: AUSTRALIA NEWCREST/EARNINGS