Lawmaker Regina Ip backed the government's move to impose sanctions against six individuals wanted for alleged national security offences, saying it was necessary to demonstrate to the public that there are consequences for breaking the law.

"I doubt very much whether these absconders will actually come back to Hong Kong to face the law," the former security minister said.

"But it will demonstrate to any potential absconders that the government takes absconding highly seriously, and there are punitive measures directed against them if they do run away from the law."

Another former security chief-turned-lawmaker, Lai Tung-kwok, said the purpose of revoking the fugitives' passports was to limit their mobility.

But he admitted they could still visit countries using other travel documents, such as a British National (Overseas) passport which is not recognised in Hong Kong.

Meanwhile, barrister and Executive Councillor Ronny Tong warned that anyone who joins paid subscriptions of websites or channels run by the six persons may be seen as providing financial aid to them.

Tong said people may still fall foul of the law by simply "following" such pages, as this may indirectly help the wanted persons generate revenue through advertisements.