Chinese companies are expected to face tougher scrutiny in the US following Google's announcement that its systems and those of 20 other companies had been attacked by hackers in China.

Huawei, China's largest telecommunications maker, among others has already faced roadblocks when seeking to invest in the US, win government contracts or sell products considered vulnerable to security leaks.

“This will increase the intensity of already substantial reviews of Chinese transactions in areas related to national infrastructure, which includes technology,” said Jamie Gorelick, who served as deputy attorney-general during the Clinton administration and is now a partner at law firm Wilmer Hale.

The Obama administration signalled its concern about Chinese investment in critical infrastructure when it made clear that it was prepared to reject a bid by a Chinese company to invest in a small Nevada gold mining operation because it was located near a naval air station.

The Google fracas might also spell trouble for Chinese companies already operating in the US.

“This is clearly a step back for a number of companies in this country on a very broad level,” said an executive at a technology company who asked not to be named. “It might not mean that we will be losing orders, but this will make for a less conducive environment.”

A source close to Huawei said: “My first gut reaction to the Google news was, this doesn't add any brownie points. This brings the issue about trust to the fore again.”