Child sex offenders were sentenced to an average of 3.84 years in prison last year, a lawmaker said Friday, calling for stronger punishment for the crime.

Last year, a total of 448 people sexually abused children under the age of 13, Rep. Seo Young-kyo of the main opposition Democratic Party said, citing data from the Supreme Court.

Seo serves on the parliamentary legislative and judiciary committee.

The average jail term for those sex offenders was 3.84 years, up slightly from 3.46 years in 2010 and 3.7 years in 2011, she said. 

"Sex offenses against children should never be tolerated," Seo said. "I will do my best to ensure that the revision to the sexual protection of children and teenagers act, which calls for stronger punishment, is passed as soon as possible."

The average jail term for sex crimes against those aged 13 or above was 3.36 years in 2012, up from 3.34 years in 2010 and 3.17 years in 2011, according to the data. (Yonhap News)