Chief Executive Carrie Lam says lawmakers must still pass new extradition laws before their summer break, even though the man at the heart of a case used to justify the urgency of new legislation was on Monday jailed for 29 months.

Chan Tong-kai, who is believed to have murdered his girlfriend in Taiwan last year, was jailed by Hong Kong's High Court over money laundering charges relating to property stolen from the victim.

But responding to the sentencing, Lam said Chan could actually be out of prison by October and therefore there is still an urgent need to bring in new laws to allow one-off extradition deals, in this case allowing the SAR authorities to surrender Chan to Taiwan.

"We have to ask ourselves whether we will continue to tolerate this loophole in our system, in the return of fugitive offenders. To the extent that we'll make Hong Kong a haven for these offenders of serious crimes all over the world," she said.

Lam was speaking a day after tens of thousands of people took to the streets to oppose the planned law changes in a second major protest over the controversial issue.

Asked by reporters whether she would consider withdrawing the bill from Legco or further consultations with the public, the CE said she respects people's views, while also noting that "there are always many rallies in Hong Kong".

"Hong Kong is a very free society. We respect the expression of opinions by the people of Hong Kong in an orderly manner and we are always willing to listen," she said.