Security Secretary Chris Tang on Sunday brushed aside criticisms that police requirements for demonstrations are "discriminatory", saying some people who find fault with the arrangement are trying to incite hatred and endanger national security.

Tang's comments came after some people complained about a decision to instruct people taking part in a march protesting against reclamation plans in Tseung Kwan O last week to wear numbered badges, to ensure compliance with a limit on the size of the event.

Tang said officers would conduct risk assessments and require measures as needed to identify participants, control the scale of the event and prevent it from being hijacked to endanger security.

He says he believes people are happy to comply with the requirements.

"If you go to the Convention and Exhibition Centre, you'll see most conference-goers [wearing badges]. It is absolutely not discriminatory or derogatory," he told reporters.

"But unfortunately some people stirred up other's emotions and smeared the government on purpose," he added.

"I believe some of those people aim to incite discontent and hatred against the government, in a bid to endanger national security and make Hong Kong no longer peaceful."

Separately, the minister criticised a political cartoon in the Ming Pao newspaper on Saturday, which he said had wrongly stated that HK$20 billion had been set aside for upgrading police equipment and building more prisons.

The minister said the comic could mislead people to think that the new police IT system, which will cost HK$5.2 billion, is for monitoring Hong Kong people. In fact, he says, its purpose is to facilitate rescue operations.