China's top legislature is investigating on the public call of repealing the crime of sex with underage prostitutes and identifying the offence as rape, said a lawmaker on Sunday.

No timetable for the amendment, however, was given by Zang Tiewei, an official with the Commission for Legislative Affairs of the National People's Congress (NPC) Standing Committee.

Under the current law, people who have sex with prostitutes under 14 years old face a maximum of 15 years in prison, while those convicted of raping a child may face the death sentence.

The question of whether to scrape the crime of sex with underage prostitutes has been controversial among legal professionals since it was written into the Criminal Law in 1997.

Speaking at a press conference on the sidelines of the ongoing NPC session, Zang said the legislature has carried out multiple investigations on the issue and listened to opinions from scholars, various departments and legislators.

Zang said the legislature also analyzed a large number of such cases from grassroots judicial departments.