A couple of profitable e-commerce and content-sharing mini programs formerly embedded on messaging platform WeChat face a sudden block by parent company Tencent Holdings Ltd.

WeChat is starting "rectification" of the application and blocking third-party programs that haven't complied with regulations, Tencent said in a statement and quoting a compliance administration notice issued Dec. 11 by its WeChat security center.

Many businesses benefit from embedding their mini programs on WeChat - which has nearly 1.2 billion active users every month. With a simple swipe on the WeChat interface, users can search and access myriad mini programs. Nearly one-third of miniprogram traffic comes from searching the WeChat interface, according to public information.

"Users have complained that third-party external links have enticed them to share or misled them to download the apps," Tencent said in its statement. The company said it had prompted the third parties to design a better user experience - but some remained in violation of terms.

Popular social media and e-commerce application Xiaohongshu - also known as RED - Pinduoduo Inc.s' livestreaming product Duo Duo Live, short video platform Haokan Video, question-and-answer website Zhihu and even Tencent's own products QQ browser and QQ Music are on the block list.

Users will no longer be able to directly open links for these programs on WeChat and need to copy and paste them into a browser to visit.

Tencent's restrictive measures stirred up online discussion. Weibo chat saw as many as 210 million views on the topic as of late Wednesday.

"If the block didn't come, I would have to block my relatives and friends on WeChat who often share with me annoying shopping links," one contributor said.

Despite some positive feedback that Tencent's efforts provide protection for a healthier social media, others are concerned it is an act of monopolization. 

Last week, TikTok parent company ByteDance Ltd. accused Tencent of blocking its WeChat mini programs Feishu Conference and Feishu. Known as Lark overseas, Feishu provides a combination of features offered by business communication platforms Slack and Google Docs. 

"Though the review status has shown 'passed', WeChat still can block the product for no reason," ByteDance's vice president overseeing Feishu Xie Xin said in a post. He added that the company respected Tencent's market position and influence but ByteDance "does not agree with Tencent's reliance on its monopoly position to block Feishu and harm the enterprise and user experience."

China's social commerce boomed in 2018 and, since then, has been prominent in retail sales. Social commerce sales in China were $186.04 billion in 2019 - nearly 10 times the sales in the U.S., according to eMarketer.

Tencent initially rolled out a similar regulation Oct. 28, 2019, aimed at regulating content through external links on WeChat. It detailed 20 rules and, in particular, prohibited practices such as enticing users to share links in return for "red envelope" bonuses and for group shopping discounts. 

The 2019 regulation blocked some violations such as the Ctrip mini program, however. E-commerce companies relying on group discount campaigns as a business model were hard put to comply - so Tencent's past warnings went largely unheeded, analysts said.

China's social commerce is expected to grow to $315.50 billion in 2021 - accounting for 13.0% of combined retail e-commerce sales.