Australia is on track to host the world's two biggest lithium mines as soaring sales of electric vehicles and mobile phones in China drives demand for the rare metal.

Surging production of electric vehicles and the lithium batteries that power them is expected to underpin demand for lithium, the key Diggers and Dealers mining industry conference has heard.

Pilbara Minerals, which is developing the Pilgangoora Project in the iron-ore rich Pilbara region of Western Australia, has recently signed an offtake agreement with Chinese firm General Lithium and plans to start mining next year.

Opposition Leader Bill Shorten examines a lithium battery container during a visit to a renewable energy manufacturer, in Belmont, WA. The US and Chinese-owned Greenbushes lithium mine in south Western Australia is now the world's biggest lithium mine. Alex Ellinghausen

Pilbara chief executive Ken Brinsden, the former boss of iron ore miner Atlas Iron, told the conference in Kalgoorlie that investors will focus on the value of new lithium developers and choose low-cost operations close to a port as they did with iron ore.

"It's going to take a big project like ours to make a dent in the demand side," Mr Brinsden told reporters at Diggers and Dealers on Tuesday.