A number of the United States' biggest chipmakers have sold millions of dollars in products to Huawei despite a Trump administration ban on the sale of US technology to the Chinese telecommunications giant, according to four people with knowledge of the sales.

Since the Commerce Department enacted the ban in May, US companies including Intel and Micron have found ways to sell technology to Huawei, said the people, who spoke on the condition they not be named because they were not authorised to disclose the sales.

The components began to flow to Huawei about three weeks ago, the people said.