National lawmakers have filed 514 bills with the secretariat of the fifth session of the 12th National People's Congress (NPC), an official said Monday.

According to Kong Ping, an official with the secretariat, 492 of the bills deal with legislation, 16 with NPC supervision and six with other issues.

Major topics include deepening the national supervisory system reform, improving the legal system, developing socialist democracy, boosting cultural sectors, enhancing people's well-being and promoting ecological protection.

Around 68 percent of the bills are based on investigations, inspections or interviews, Kong said.

Bills from NPC deputies can be legally binding if they are adopted. Last year, 462 bills were filed.

The secretariat has also received 8,360 suggestions from NPC deputies, which are less formal and will not be legally binding.