Justice Secretary Paul Lam told Legco on Monday that a proposal to enable the authorities to bar certain national security suspects from consulting a lawyer for two days is necessary – in case the legal professional they turn to is actually an accomplice.

Lam told a Legco bills committee on Article 23 security legislation that if the police believe a suspect in detention is trying to undermine security rather than seeking advice, they can ask the courts for a 48-hour ban on access to any legal representation.

"Maybe we know this person has many accomplices, who may be lawyers. But we don't know which law firm they're working for and whether they're barristers or solicitors. In this case how can we ensure there wouldn't be a risk that the lawyer might help the suspect to, for example, handle proceeds from a crime and tip someone off?" he questioned.

"We wouldn't be able to name the lawyer to the court, but such a risk exists. The only way to deal with this is by banning the suspects from meeting any lawyer within a 48-hour period because there's too big a risk."

Lam said he is aware that such a ban would stop a suspect from enjoying a right protected by the Basic Law, and such a restriction could not be imposed indefinitely.

Officials said the 48-hour ban would not be extendable.

Lam said that in cases where authorities know that a specific lawyer is undermining security, police would be able to ask the courts to completely ban this person from meeting a suspect in detention.