US Commerce Secretary Gina Raimondo on Saturday urged lawmakers, Silicon Valley and US allies to stop China from getting semiconductors and cutting-edge technologies key to national security.

Speaking at an annual national defense forum in Simi Valley, California, Raimondo called Beijing "the biggest threat we've ever had" and stressed "China is not our friend."

The world's top two economies are locked in a fierce commercial and geopolitical rivalry, in which her department plays a leading role.

In October, Raimondo unveiled a series of restrictions on the export of advanced chips to China, including those used in the development of artificial intelligence (AI), to prevent their use by Beijing for its military.

"I know there are CEOs of chip companies in this audience who were a little cranky with me when I did that, because you're losing revenue. Such is life, protecting our national security matters more than short term revenue."

"Newsflash: democracy is good for your businesses. Rule of law here and around the world is good for your businesses," she said.

Raimondo noted that Nvidia, maker of the most sophisticated chips needed to develop the latest generation of AI, had developed a product that performs just below the limit set by her department for export to China.

"That's what industry does," she acknowledged, but added, "That's not productive."

"Every day China wakes up trying to figure out how to do an end run around our export controls... which means every minute of every day, we have to wake up tightening those controls and being more serious about enforcement with our allies," she said.

Raimondo stressed that her department needs better funding to effectively carry out its mission.

"I have a $200 million budget. It's like the cost of a few fighter jets. Come on," she said. "Let's go fund this operation like it needs to be funded so we can do it, we need to do to protect America."

"America leads the world in artificial intelligence... America leads the world in advanced semiconductor design," Raimondo said. "That's because of our private sector.

"No way are we going to let (China) catch up."