Australia's Lynas Rare Earths said on Friday there will be a planned shutdown of all its operations in Malaysia except the segment for mixed rare earth carbonate processing in the December quarter.

During the shutdown, key personnel from the Malaysian cracking and leaching segment will be deployed to assist with the start-up process of its rare-earths processing facility in Kalgoorlie in Western Australia, Lynas said.

The company also reported a 21.8% fall in first-quarter revenue on Friday, hurt by lower product prices and continued accumulation of inventory.

The world's largest producer of rare earths outside China said sales revenue was A$128.1 million ($81.04 million) for the three months to Sept. 30, compared with A$163.8 million a year ago and a consensus estimate of A$159 million, according to Barrenjoey.

($1 = 1.5808 Australian dollars)

(Reporting by Echha Jain and Adwitiya Srivastava in Bengaluru; Editing by Devika Syamnath)