The government on Tuesday said it plans to double the maximum penalty for illegally manufacturing and trafficking firearms to up to 20 years behind bars.

This is to bring local laws in line with a United Nations firearms protocol, which began to apply in the country, including the SAR, early last year.

Security minister Chris Tang said to reflect the seriousness of the crime, officials plan to make manufacturing firearms, their components and ammunition a separate offence.

"No person should manufacture firearms or ammunition unless they're doing it by way of trade or business, or holds a dealer's licence. As this may be a national security threat, we will enhance the prison term to 20 years instead of 10," he said at a security panel meeting at the legislature.

He told lawmakers that in the past five years, the authorities uncovered complete firearms on 12 occasions, while detecting two cases of firearm manufacturing and three cases of illegal imports.

Tang said the new offence would cover those who use 3D printing techniques to manufacture a legitimate firearm, while those who print air guns without a licence could be subject to punishment under existing laws.

He said the government plans to table a bill to the legislature in April, and complete the legal changes within this year.