May 12 (Bloomberg) -- Glencore International AG, a metals trader and producer, asked Australian regulators to block Centennial Coal Co.'s A$393.4 million ($302 million) bid for Austral Coal Ltd.

Glencore, based in Baar, Switzerland, owns 6.4 percent of Austral and said last month it will retain options to buy about 6.5 percent more. The company said Centennial should have disclosed plans to close the Munmorah coal mine in New South Wales, Australia, before bidding for Austral in February.

The shutdown, announced on April 29, affects the value of Centennial shares and its all-stock bid, Glencore said, according a statement today by Australia's Takeover Panel. The panel said it hasn't decided whether to grant Glencore's request that Austral investors be allowed to withdraw acceptance of the bid.

Nobody answered telephone calls made to Centennial and Austral in Sydney. Glencore spokeswoman Lotti Grenacher wouldn't comment. The company owns coal mines in Colombia and 40 percent of Zug, Switzerland-based Xstrata Plc, the world's largest exporter of coal burned in power plants.

Shares of Centennial closed in Sydney unchanged at A$4.78. They have gained 11 percent since the company offered one share for each 3.7 Austral shares on Feb. 23. The bid values Austral at A$1.29, 27 percent more than before the bid.

To contact the reporter on this story: Simon Casey in London at scasey4@bloomberg.net.

Last Updated: May 12, 2005 12:19 EDT