Housing minister Winnie Ho on Thursday said the government was not including cage homes and cubicle units under the planned new regulatory regime for subdivided flats, because those are already subject to an existing licensing system.

There have been calls for the government to put these so-called bed space units under the future basic housing unit regime, which would subject flats to requirements such as a minimum size.

But the housing chief said there's a public misconception about this.

"'Bed space' units in various forms – including 'cage homes', 'coffin homes' and 'space capsule' units – are already regulated by the licensing regime under the Bedspace Apartments Ordinance," Ho wrote in an SCMP opinion piece.

"Regulation under the regime for basic housing units would only duplicate regulations and is therefore unnecessary."

Ho said the government estimates that around 80,000 basic housing units would still be available in the market after the new laws are introduced.

Coupled with the fact that more public housing will be available in the coming years, she said there shouldn't be much room for rents to rise significantly for subdivided flats.

Ho added that as tackling subdivided flats is her bureau's top priority, the government is striving to pass legal changes by the end of the year and would then implement new regulations in a gradual and careful manner.

Landlords would be given up to a year and a half to register the flats, followed by a grace period of up to two years for working things out with tenants before flat conversion.

The minister said after the completion of registration, officials would decide on the time frame for law enforcement.

She said enforcement would be carried out in an orderly manner, to avoid displacing affected households.