Chinese customs officials have been told to strengthen inspections of mobile devices with Internet-based maps and to seize items using illegal maps, according to the national mapping authority.

The detained goods will be transferred to local bureaus of the National Administration of Surveying, Mapping and Geoinformation (NASMG) for further investigation, said a report from the Legal Daily, which cited an anonymous official from the administration.

"Illegal maps" include unauthorized maps with mistakes in the drawing of a country's border, missing important islands or leaking confidential geographic information, the report said.

The NASMG has noticed that many Internet-based maps used by cell phones and tablet computers were actually "illegal maps."

Telecommunications authorities are also required to work with the NASMG to improve the supervision on mobile devices. Failure to provide proper maps may result in revocation of network licenses, the report added.

A draft regulation on mapping activities has set out more restrictions for Internet map services, which requires providers to place data servers within China's territory and use only approved maps.

Failure to demonstrate China's complete territory when drawing up related maps may result in tougher punishment, according to a draft, which is currently open for public to give comments until Oct. 26.