Officials had requested the feature to tackle fake accounts, which they say had been used to spread hate material.
They noted WhatsApp - which is owned by Facebook - already had the requirement.
The social network met with the local authorities last week - a month after a man was sentenced to death in Pakistan for allegedly posting blasphemous material on Facebook.
The public prosecutor involved said he believed it was the first time the death penalty had been awarded in a case related to social media.
Earlier in the year, the Interior Minister Chaudhry Nisar threatened to permanently block any social media platform that refused to co-operate with his anti-blasphemy crackdown.
The minister recently met with Facebook's public policy chief Joel Kaplan to discuss the matter.
The country briefly blocked Twitter in 2012 after some users reportedly encouraged others to draw images of the Prophet Muhammad, which is forbidden under Islam.
For now, Facebook will continue to authenticate new accounts via an email address rather than a mobile number.
However, a government spokesman said the firm had promised to "look into the government's concerns on a priority basis", after the most recent discussions.
For its part, the US company put a different spin on proceedings.
"Facebook met with Pakistan officials to express the company's deep commitment to protecting the rights of the people who use its service, and to enabling people to express themselves freely and safely," said a spokeswoman.
"It was an important and constructive meeting in which we raised our concerns over the recent court cases and made it clear we apply a strict legal process to any government request for data or content restrictions."
Facebook has rejected Pakistan's demand to link new accounts on its main service to users' mobile phone numbers.