WhatsApp on Friday postponed a data-sharing change as users concerned about privacy fled the Facebook-owned messaging service and flocked to rivals Telegram and Signal, AFP reports.

The smartphone app, a huge hit across the world, cancelled its February 8 deadline for accepting an update to its terms concerning sharing data with Facebook, saying it would use the pause to clear up misinformation around privacy and security.

Hong Kong's privacy watchdog was among those to call on WhatsApp to provide more clarity before going ahead with the changes.

"We've heard from so many people how much confusion there is around our recent update," WhatsApp said in a blog post. "This update does not expand our ability to share data with Facebook."

It said it would instead "go to people gradually to review the policy at their own pace before new business options are available on May 15."

WhatsApp's new terms were unpopular among users outside Europe who do not accept that they were given a deadline to be cut off from the service.

The update concerns how merchants using WhatsApp to chat with customers can share data with Facebook, which could use the information for targeted ads, according to the social network.

"We can't see your private messages or hear your calls, and neither can Facebook," WhatsApp said in an earlier blog post.

"We don't keep logs of who everyone is messaging or calling. We can't see your shared location and neither can Facebook."

Location data along with message contents is encrypted end-to-end, according to WhatsApp.

"We're giving businesses the option to use secure hosting services from Facebook to manage WhatsApp chats with their customers, answer questions, and send helpful information like purchase receipts," WhatsApp said in a post.

"Whether you communicate with a business by phone, email, or WhatsApp, it can see what you're saying and may use that information for its own marketing purposes, which may include advertising on Facebook."

Encrypted messaging app Telegram has seen user ranks surge on the heels of the WhatsApp service terms announcement, said its Russia-born founder Pavel Durov.

Encrypted messaging app Signal has also seen a huge surge in demand, helped by a tweeted recommendation by billionaire tech entrepreneur Elon Musk.

WhatsApp is postponing its data-sharing change till May 15. File Photo: AFP

WhatsApp puts off privacy policy change as users flock to rival apps