"There is reputable evidence that there are kids under 13 who are lying about their age to get on to Facebook," Sunday Times quoted Simon Milner, Facebook's head of policy in Britain as saying.
"Some seem to be doing it with their parents' permission and help," Milner said.
If the decision to lift the ban is implemented, a flood of new users are likely to sign up to the social network, which floated on the stock market last week for USD 105 billion last week.
The number of people with profiles - currently estimated at 900 million active users - would probably hit the iconic one billion mark, meaning that more than one in seven people in the world would be an active user of the site.
However, Milner said the decision to allow children to create profiles was still at a very early stage.
Milner said he will launch a debate about the minimum age in Britain when he appears next month at Wellington college, Berkshire.
"We have a strict under-13 rule because of legal issues in America," he said.
"We apply the same rule all over the world. But a lot of parents are happy their kids are on it. We would like to hear from people what the answer might be."
Supporters of the minimum age believe it helps shield children from cyberbullying and inappropriate contact with adults.
Past surveys in the UK have suggested that one in three British children has been the victim of abuse on the Internet.
The poll, commissioned by charity Beatbullying in 2009, also revealed that girls are up to four times more likely to face online bullying than boys, Daily Mail reported.
Some school bullies have even set up Facebook groups allowing dozens of people to band together to abuse classmates, it said.
Facebook has responded to criticism in the past by adding a number of safety features to the site to attempt to combat online bullying.