Lawyers for Levandowski say their client stole nothing and they look forward to proving his innocence at trial.

The 33-count indictment largely mirrors allegations that the Waymo unit of Google's parent company Alphabet, where Levandowski had worked, had made in a civil lawsuit against Uber in 2017, which was later settled.

Levandowski could face many years in prison and a fine if convicted. He is expected to appear later on Tuesday in federal court in San Jose, California.

The prosecution of Levandowski is one of Silicon Valley's highest-profile trade secret theft cases, as engineers race to develop technology for self-driving cars, which industry experts view as a $US1 trillion market opportunity within three decades.

Prosecutors accuse Levandowski of stealing materials in late 2015 and early 2016 related to Waymo's self-driving car technology.

They say he did this after deciding to leave and form his own self-driving company, Ottomotto, which Uber later bought.

The alleged stolen materials included details related to Lidar, a crucial sensor technology, according to the indictment.

All people are free to change jobs, US Attorney David Anderson said at a news conference. "But what we cannot do is stuff our pockets on the way out the door."

Anderson declined to answer a reporter's question on whether Uber could also face any criminal charges. Uber did not immediately respond to a request for comment.

Levandowski left Waymo in early 2016 and eventually took over Uber's self-driving car project before being fired.

"For more than a decade, Anthony Levandowski has been an industry-leading innovator in self-driving technologies," and the government's case is a "rehash" of discredited claims, his lawyer Miles Ehrlich told reporters at the San Jose courthouse.

Lawyers for Levandowski said the downloads in question occurred while their client was still working at Alphabet, and that he was authorised to use the information.

Pronto, a self-driving software company that Levandowski co-founded in 2018, on Tuesday said in a statement that it replaced him as chief executive with Robbie Miller, who had been chief safety officer. It said it was it was "fully supportive" of Levandowski and his family.

Legal battles involving Levandowski have cost Uber precious time on its self-driving car project, which is important to its long-term profitability.

Levandowski did not testify at the trial between Waymo and Uber before the case was settled, and has not spoken publicly about it.

The lawsuit was another public controversy for Uber, which was trying to emerge from scandals under former chief executive Travis Kalanick, including over how the company treated female employees. Kalanick had called self-driving cars an "existential" threat for the ride-hailing company.

Prosecutors said there remain legal limits to competition.

"Silicon Valley is not the Wild West," FBI special agent in charge John Bennett said at the news conference. "The fast pace and competitive environment does not mean federal laws don't apply or they can be ignored."

Waymo said it appreciated prosecutors' work on the case. "We have always believed competition should be fuelled by innovation," a spokeswoman said in a statement.

Australian Associated Press