China’s military is ready and able to ''safeguard'' Chinese sovereignty in Hong Kong, the commander of the city-based garrison has said.

Chen Daoxiang, the People’s Liberation Army commander in Hong Kong, was speaking days after China announced plans to introduce a draconian new national security law that threatens many of the semi-autonomous city's civil liberties and political freedoms.

"Garrison officers and soldiers are determined, confident, and capable of safeguarding national sovereignty and development interests and the long-term prosperity and stability of Hong Kong," Chen said Tuesday, adding that the Hong Kong Garrison viewed the national security law as "conducive to deter separatist forces and external intervention."

The warning came as protesters prepared for further demonstrations on Wednesday when the legislature starts debate on a controversial bill to criminalize ridicule of the Chinese national anthem.

Hong Kong’s chief executive, Carrie Lam, maintained full support for the move, saying the Hong Kong government had been unable to pass the laws itself for 23 years and was unlikely to in the near future.

At her weekly press conference on Tuesday, Lam defended the legality of NPC promulgating the law as ''sound and robust''.

Related: Hong Kong's leader Carrie Lam says security laws will not affect their rights and freedoms