Housing minister Winnie Ho said on Sunday that the government could start prosecuting landlords of illegal subdivided flats by the end of 2026 at the earliest, with the possibility of jail terms.

In his Policy Address last week, Chief Executive John Lee announced plans to regulate subdivided units, renaming the vetted flats "basic housing units" (BHUs) and making those smaller than 86 square feet illegal.

Ho said if all goes smoothly, laws would be passed by the end of next year, and that would be followed by a period for landlords to register and a grace period for them to renovate the flats to meet the new requirements.

"[If] a one-year registration period is enough, that would take us to the end of 2026," she said on a Commercial Radio programme.

"If landlords don't register during the period and continue to operate homes that violate our regulations, then law enforcement could begin at the end of 2026, or at the start of 2027 at the earliest. That's within the term of the current administration."

Deputy Financial Secretary Michael Wong, who heads a government task force on the matter, said the timeline is not set in stone, citing an upcoming public consultation exercise and discussion with lawmakers.

Wong also said he doesn't think there'll be a significant drop in supply, pointing to the availability of more BHUs in the market in future.

He added that among tenants of current subdivided flats, 60 percent of them are eligible to apply for public housing and the rest could look for BHUs or transitional housing units, insisting everyone will have a roof over their heads.

On a TVB programme, Lee said landlords of subdivided flats are allowed to raise rents by a maximum of 10 percent under existing rent-control laws. The CE also said tenants can move from one BHU to another in future, in the event rents go up.