WASHINGTON (Reuters) - The Biden administration is drawing up a list of advanced Chinese chipmaking factories barred from receiving key tools, three people familiar with matter said, to make it easier for companies to stem technology flows into China.

The list could be released in the next few months, one of the people said.

The Commerce Department in 2022 barred U.S. companies from shipping equipment to Chinese factories producing advanced chips, as the U.S. seeks to severely limit Beijing's technological advances over national security concerns.

But companies say it is difficult to pinpoint which factories in China produce advanced chips and have long urged the Commerce Department to publish a list.

The effort shows the United States is taking pains to strengthen its existing chips restrictions on China by making it easier for U.S. firms to comply with restrictions.

The Commerce Department declined to comment and the Chinese Embassy in Washington did not immediately respond to a request for comment.

Officials addressed the companies' request at an annual export controls conference in Washington, D.C. this week.

"People are like, 'please, just tell us which are these advanced [factories] that you really care about,'" said one official, speaking on a panel, and confirming work on the list.

"It's probably not going to be an exhaustive listing, if we can do that. But the more that we can help identify what are these facilities that we have a concern with, hopefully that's going to help," the official added.