Police commissioner Joe Chow said on Saturday provisions under the city's national security legislation clearly state what constitutes an offence, stressing that the force would take action against any violations.

Chow was speaking after two men were arrested this week for their alleged roles in handling financial transactions linked to a wanted national security suspect.

It's believed to be the first time the police have applied the Safeguarding National Security Ordinance's provisions targeting the handling of funds belonging to fugitives.

Asked if the police action would a set a precedent, Chow said: "The pieces of national security legislation are written clearly, stipulating a number of legal elements.

"The police will take action when someone breaks the law.

"There will always be a first case and there's no such thing as setting a precedent."

Chow, who took over the reins of the force last month, noted that the work in bringing down crime rates has "made some good progress" in the first quarter of this year.

He vowed to make good use of technology to stamp out crimes and increase the detection rate.