China says foreign criticism of court sentences handed down on Tuesday in Hong Kong's largest national security trial thus far tramples on the city's rule of law.

Speaking at a regular press briefing in Beijing, spokesman Lin Jian said no one can engage in illegal activities in the name of democracy and attempt to escape legal punishment.

Lin also said Beijing firmly supports Hong Kong's efforts to safeguard national security.

The US consulate in Hong Kong said Washington strongly condemns the sentencing.

Australia said it was gravely concerned about the fate of one of its citizens, Gordon Ng, who was jailed for seven years and three months.