A fingerprint scanner is tested at a police station where all residents in Beijing will have their fingerprints taken for identity cards, May 26, 2013. [Photo/CFP]

The number of people with duplicate ID numbers has been cut from 1.68 million in 2009 to just 486 today, a senior official at the Ministry of Public Security said on Wednesday.

The number issued by the ministry identifies Chinese citizens within the country, and it has a function similar to that of the Social Security number in the United States.

The ministry will cancel all duplicate ID numbers by the end of 2016, realizing the goal of one ID number and one hukou (residence registration) for each citizen, said Huang Ming, vice-minister of public security.

"Duplicate ID numbers are a historical problem that emerged in the 1980s when the system was launched," said Chen Tianben, an associate professor at the People's Public Security University. "Errors occurred during the period when all ID numbers were registered by police officers personally. Citizens with duplicate ID number are in their 40s or older."

The ministry started to issue ID numbers in the 1980s along with first-generation ID cards that ceased to be valid on Jan 1, 2013. Second-generation ID cards have been issued since 2004.

The ministry said police made special efforts last year to deal with the problem of incorrect, fake and duplicate ID cards to ensure the accuracy of the country's records.

Officers found and canceled 2.5 million duplicate or incorrect hukou records last year and 790,000 in 2013.

They dealt with 238 cases involving counterfeiting and selling fake ID cards or hukou documents last year, and 313 people received penalties, in some cases including detention.

"Duplicate ID numbers give criminals a legal loophole and make it easy to create fake ID cards," Chen said.

"They also make it difficult for police to track down criminals. For example, if two people share the same ID number and one of them breaks the law, it is difficult for the police to tell who is the real criminal based on the ID number."

The ministry has introduced image-matching technology to check ID information.

Thirty provinces and municipalities are using the technology to cross-check details, and this has led to the detection and cancellation of 587,000 duplicate hukou records.

A total of 176 police officers and 57 legal assistants have been punished for creating fake IDs.

In 2013, Gong Ai'ai, a woman dubbed "Sister House" by Chinese netizens because she had more than 40 properties in Beijing, was jailed for three years for forging ID cards and residency records.

A former police officer in Shaanxi province was sentenced to a year in prison for helping Gong obtain the fake cards.

Dai Peng, director of the Criminal Investigation College at the People's Public Security University, said the cancellation of duplicate ID numbers and tighter hukou administration would prevent "naked officials", whose families live abroad, from fleeing or transferring assets.

Xinhua contributed to this story.