According to NDTV's sources, the government has told Meta that the feature cannot be rolled out until consultations on the matter are completed.
Feature aimed at protecting phone number privacy
The proposed feature would allow WhatsApp users to choose a unique username and connect with others without sharing their phone numbers, a move aimed at enhancing user privacy and reducing unwanted access.
At present, users generally need a phone number to connect with someone on the messaging platform.
Meta had planned to introduce the feature in phases. Starting this week, users were expected to be able to reserve their preferred usernames, while the wider rollout was scheduled for later this year.
The company said it opened early reservations because of WhatsApp's global user base of more than 3 billion people.
In a statement, Meta said the feature is "designed to protect the privacy of your phone number" by allowing people to communicate using usernames instead of mobile numbers in certain situations.
Rollout paused pending government consultation
The government's concerns over the feature have not been made public.
However, it has sought a detailed explanation from Meta on the proposed rollout and its implications.
Until the consultation process is complete and the government's queries are addressed, the username feature will remain on hold, NDTV's sources said.