A lithium mine in WA’s south is set to double in size by next year, creating hundreds of new jobs in the process.

Tianqi’s lithium mine in Greenbushes, about 90km south of Bunbury, is already the biggest lithium mine on the planet and supplies a third of the globe.

But an expansion is set to create 400 new jobs, and all while the company also builds the biggest lithium processing plant in the world – in Kwinana.

Camera Icon The mine in Greenbushes in already the biggest lithium mine in the world. Credit: 7 News

“It's a great opportunity for people living in the Kwinana area,” Tianqi general manager Phil Thick said.

“Five-hundred (new jobs) over the next 12 months as we speak.”

Lithium is used to make batteries for the world’s mobile phones, electronics and electric cars, with demand “far out-stripping supply”, according to Mr Thick.

Camera Icon The new Kwinana processing plant. Credit: 7 News

“Western Australia has historically been very good at digging rocks out of the ground and sending them overseas,” he said.

More than half of the world’s lithium is already produced in WA. By 2025, it is predicted lithium will bring in more money for Australia than iron ore.

“This is our big chance,” Curtin University professor Peter Newman said.

Camera Icon The lithium mine is set to double in size. Credit: 7 News

“We’re talking hundreds of thousands of jobs.”

According to Seven News, it is understood the State Government has a secret working group in place to keep lithium money and jobs in WA.