SINGAPORE—Some Chinese state-run companies are restricting employees’ use of Tencent Holdings Ltd.’s popular domestic messaging app, citing security concerns, according to people familiar with the matter.

This week, managers at at least nine state-run companies, including some of the nation’s largest, such as China Mobile Ltd., China Construction Bank Corp. and China National Petroleum Corp., told employees that any chat groups set up for work purposes on Weixin—Tencent’s dominant messaging app in China—could contain sensitive...

SINGAPORE—Some Chinese state-run companies are restricting employees’ use of Tencent Holdings Ltd. ’s popular domestic messaging app, citing security concerns, according to people familiar with the matter.

This week, managers at at least nine state-run companies, including some of the nation’s largest, such as China Mobile Ltd. , China Construction Bank Corp. and China National Petroleum Corp., told employees that any chat groups set up for work purposes on Weixin—Tencent’s dominant messaging app in China—could contain sensitive information and should be shut down and deleted, the people said.

They also ordered employees to be cautious about using Weixin, which is the domestic sister app of WeChat, for work-related communications, some of the people said. These state firms haven’t publicly disclosed any security concerns over Weixin.

The move comes as Beijing intensifies scrutiny into internet giants including Tencent, China’s most valuable company, as well as Tencent’s data-collection practices.

“Many companies around the world are moving towards enterprise software to meet their internal communications needs,” Tencent said in a statement, adding that the company offers WeCom, an office collaboration app, as a solution.

On Wednesday, China’s Ministry of Industry and Information Technology told app stores that Tencent must obtain government approval before updating existing apps or launching any new apps, according to a ministerial notice reviewed by The Wall Street Journal. Tencent on Wednesday said it regularly cooperates with relevant government agencies to ensure regulatory compliance. The Ministry of Industry and Information Technology referred the Journal to an earlier state media report in which it confirmed the information in the notice.

China Mobile, China Construction Bank and China National Petroleum didn’t immediately respond to requests for comments.

Over the past year, China has launched a string of regulatory actions targeting the nation’s powerful technology sector. Tencent, an online videogaming giant, has been hit by new government restrictions on online gaming time for minors. Meanwhile, regulators in July blocked Tencent’s bid to combine two big game-streaming platforms.

Tencent President Martin Lau

said in November that the tougher regulatory environment in China is the new normal and is here to stay.

Beijing’s concerns have grown recently over the power of its homegrown internet giants. With reach across all aspects of Chinese life and reams of data on its users, these companies have a unique position in society that could challenge the Communist Party’s desire to monopolize such information.

E-commerce titan Alibaba Group Holding Ltd. and mobile-services company Meituan have been hit with antitrust fines, while financial-technology firm Ant Group Co.’s blockbuster listing was scuttled late last year. Ride-hailing service Didi Global Inc., meanwhile, has been undergoing a monthslong cybersecurity review.

Tencent’s Weixin dominates Chinese social media, allowing users to chat with contacts, post updates on a feed, pay bills and hail taxis. It also offers access to government services such as Covid-19 vaccination records and contact tracing.

Many Chinese businesses, both public and private, use the app for internal and external communications. During the pandemic, many users relied on Weixin for remote working, using it on digital devices such as their smartphones or laptops.

At some of the state-run companies, the transition from Weixin to other apps could be gradual, people familiar with the matter said. Some companies have asked employees to move work-related conversations to other platforms, they said. Those include the companies’ internal-messaging platforms, DingTalk—Alibaba’s chat app largely for enterprise—and Tencent’s WeCom, they said.

WeChat and Weixin combined have more than 1.2 billion monthly active users world-wide, according to Tencent. WeCom is used by more than 5.5 million enterprises, with 130 million monthly active users, the company said.

Earlier this year, the Journal reported that a Tencent executive was held by authorities for alleged unauthorized sharing of personal information collected by WeChat. Tencent then confirmed the probe, though it said the executive never held a senior executive or managerial posts. It also said the case is related to allegations of personal corruption.

Concerns about the use of private messaging apps for work aren’t limited to China. Many global banks ban the use of personal phones for work and record calls and texts on work devices.

Meanwhile, some Chinese state-owned companies, along with military staff, have been restricted from using Tesla Inc.’s vehicles over Beijing’s concerns that data the cars gather could be a source of national-security leaks. Tesla’s chief executive, Elon Musk, said the company would never provide the U.S. government with data collected by its vehicles in China or other countries.

—Raffaele Huang contributed to this article.

Write to Keith Zhai at keith.zhai@wsj.com