Social networking site Facebook has said it is having approximately 50 million duplicate accounts besides 22 million of misclassified and undesirable accounts.

According to a Facebook's statement as on December 31, 2012, it has 1.06 billion monthly active users (MAUs) worldwide including 71 million in India.

"We estimate, for example, that "duplicate" accounts (an account that a user maintains in addition to his or her principal account) may have represented approximately 5.0% of our worldwide MAUs as of December 31, 2012," Facebook said in its report to Securities and Exchange Commission of USA.

Facebook said it identifies "false" accounts, by way of dividing into two categories-- user-misclassified accounts, where users have created personal profiles for a business, organisation, or non-human entity such as a pet and undesirable accounts, which represent user profiles that are determined as intended to be used for purposes that violate the site's terms of service, such as spamming.

"As of December 31, 2012, for example, we estimate user-misclassified accounts may have represented approximately 1.3% of our worldwide MAUs and undesirable accounts may have represented approximately 0.9% of our worldwide MAUs," the report said.

Facebook said it believes the percentage of accounts that are duplicate or false is meaningfully lower in developed markets such as the US or Australia and higher in developing markets such as Indonesia and Turkey.

"As such, our estimation of duplicate or false accounts may not accurately represent the actual number of such accounts. We are continually seeking to improve our ability to identify duplicate or false accounts and estimate the total number of such accounts, and such estimates may change due to improvements or changes in our methodology," the report added.

Facebook claimed to have 1.06 billion MAUs as of December 31, 2012, an increase of 25% from December 31, 2011.

"Users in Brazil, India and Indonesia represented key sources of growth in fiscal 2012 relative to the prior year," the report said.

"We had 67 million MAUs in Brazil as of December 31, 2012, an increase of 81% compared to the same period in 2011; 71 million MAUs in India as of December 31, 2012, an increase of 54% compared to the same period in 2011; 60 million MAUs in Indonesia as of December 31, 2012, an increase of 25% compared to the same period in 2011, it added.

Additionally, the site had 174 million MAUs in the US as of December 31, 2012, an increase of 8% compared to the same period in 2011.