US electric automaker Tesla Motors is to build a new multi-billion-dollar "Gigafactory" in Nevada, the western US state's senator Harry Reid announced Thursday.

The plant, plans for which were announced in July with Japanese electronics giant Panasonic, will produce lithium-ion batteries for Tesla's cars. The location of the plant had not been previously confirmed.

"Later this afternoon (Tesla boss) Elon Musk and (Nevada) Governor Brian Sandoval will officially announce Nevada is the home to Tesla's new Gigafactory," said Reid, the Senate majority leader.

"Most importantly for Nevada, this factory will create thousands and thousands of good-paying jobs and be so good for our economic development," he told a National Clean Energy Summit held in Las Vegas.

Tesla was due to hold a press conference in Reno, Nevada at 4:00 pm (2300 GMT) Thursday to unveil the plans.

The company said in July that it had opened a site in Nevada which could host the Gigafactory but that other locations were still being evaluated.

Tesla will run operations while its Japanese partner will make battery cells destined for the plant and invest in equipment and machinery, according to a joint statement released at that time.

Japanese media previously reported that Panasonic would invest as much as 30 billion yen ($290 million) in the plant.

While Tesla produces relatively few vehicles, it has become a star in the sector due to keen demand and a reputation for high quality. A surge in its share price over the past year has pushed its value over $27 billion.

Tesla's Model S sells for around $75,000 but it is working on a less expensive Model X that is expected to garner wider appeal.