The Secretary for Security Chris Tang on Sunday said he had reservations over suggestions to wipe the criminal records of people convicted of protest-related charges.

Speaking on a TV programme, Tang said about 3,000 people were prosecuted over the social unrest in 2019, and out of 2,000 closed cases 80 percent of the defendants were convicted.

He said prison officials have found 60 to 70 percent of these inmates showed remorse, and believed there's a low chance of re-offending.

When asked to comment on suggestions that inmates who behaved well should have their records wiped, Tang said: "If the offences contravened are serious, we need the relevant records to stay to maintain the operation of the society."

The security chief said prison officials were helping inmates - many of them young people - with their studies and to understand the country's history.

Authorities are also in discussions with employers to find them work in the Greater Bay Area after they've served their sentences, Tang said.