Shares of Australian rare earths miner Lynas Corp. jumped to as much as 7.4 per cent in early trade on Friday as the mining company reached a "significant milestone" with the start of operations of its highly-controversial Malaysian processing plant.

The company said the Lynas Advanced Materials Plant (LAMP) in Kuantan, Malaysia had started its first feed to kiln and that startup of operations is likewise already underway.

"This is a significant milestone for Lynas," Lynas Executive Chairman Nicholas Curtis said in a statement. "The operation of the LAMP is now a reality."

He added that as the plant progresses with its operations, real data about its security and effectiveness will eventually come out. Mr Curtis hoped this will assure people that the $800 million LAMP, the world's biggest outside China, is entirely safe for the local communities and the environment.

"We are excited to start creating value at the LAMP, and we look forward to sharing that value with all of our key stakeholders, including the communities in which we operate," he said.

The initial feeding of concentrate into the kiln will progress to continuous feed by next week.

Lynas anticipates a ramp-up period of three to four months until first commercial sales and subsequent cash generation.

At 1218 AEDT, Lynas shares were up 1.5 cents to 69 cents.