The Wall Street Journal reported that the slowing down of approvals had begun in 2018 and was affecting companies like Intel, Qualcomm and Globalfoundries.
It was also preventing such companies from moving employees from branches in other countries to offices in the US.
The delay was making a significant difference because Chinese citizens formed a big portion of the non-American citizens hired for these jobs, the report said.
There have been numerous reports in US media over the last few years about alleged theft of trade secrets by Chinese nationals.
Rules which govern the hiring of foreign nationals make it compulsory for companies to obtain licences before hiring them, as such jobs would give the employees knowledge about US technology which they could take with them when they returned home.
The US and China have been involved in a protracted trade war, with Washington insisting that China drop its insistence on technology transfers.
Last year, President Donald Trump issued an executive order blocking a deal between Singapore-based Broadcom and Qualcomm, over what were said to be national security concerns, but were better described as a step to prevent China from competing with the US.
The approvals are separate from the visas that foreigners need to obtain in order to work in the US and the degree of examination depends on the technology involved and the perceived degree of risk that it could be known to citizens of China which is considered to be an adversary by the US.
An industry insider told the WSJ: "There have been longer delays that have led us to lose candidates we thought were critical."