The Companies Registry and the Land Registry have said the requirement will come into effect on November 1.
The departments said people will also have to state the purpose of their searches and undertake not to use the information elsewhere or in contravention of the privacy ordinance.
Speaking on an RTHK programme on Tuesday, Chan said having journalists provide ID card numbers will make it easier for them to be traced by the authorities.
“In the past we were not so worried. One could write an English name or so on, and it was not so easy to identify [the reporter],” he said.
“If they have your ID card number and the name, it would be much easier. The searches were certainly done by you, if the declared purpose is ‘land sale’ and you use it in media reports, then you can be prosecuted,” he added.
Chan cited the case against former RTHK freelance producer Bao Choy, who was convicted over her investigation into the 2019 Yuen Long gang attack.
She was found guilty of violating the Road Traffic Ordinance by making false declarations when searching for the owners of cars believed to be linked to the mob violence.
“For most of the searches we do now, we are not given the option of ‘journalistic work’ as the purpose of the searches. You can choose other options like land sales or commercial affairs, but not journalism. If in the end, like in the Bao Choy case, if they see that you are using the information in a media report, they can prosecute you for using false documents or making a false declaration,” Chan said.
He also said authorities should clarify whether journalistic work is exempted under the privacy ordinance.
