Hong Kong began implementing on Sunday a law to address the long-standing issue of substandard subdivided units (SDUs) in the city.

The Hong Kong Special Administrative Region government rolled out the Basic Housing Units Ordinance, which requires owners of subdivided units in residential buildings to register their properties and meet relevant standards.

Under the principle of "registration first, enforcement later", the ordinance aims to eradicate substandard SDUs in an orderly manner and enhance the living conditions of grassroots tenants.

The law’s 48-month transitional arrangements allow flat owners and operators to gradually adapt to statutory requirements. Illegally letting SDUs with no registration and no recognition will only become a crime starting March 1, 2027.

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An HKSAR government spokesman stressed that the issue of substandard SDUs over the years had come to a critical point and there has been undisputed consensus in the community that grass-root SDU tenants should have a safe, and reasonable living environment.

He added that the SAR government has always accorded top priority to the well-being of SDU tenants and will implement the BHU regime in an orderly manner.

Under the law, SDUs must comply with minimum standards of living conditions, including requirements on minimum area, minimum height, fire safety, structural safety, separate toilets, water supply, lighting and ventilation, and separate water and electricity meters.

The Dedicated Team on Subdivided Units of the Housing Bureau began accepting on Sunday applications for registration of pre-existing SDUs, as well as applications for BHU recognition of units complying with minimum standards of living conditions.

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During the first year of the implementation of the law, owners of pre-existing SDUs should register their units to obtain a 36-month grace period in arranging their tenancies and necessary alteration works.

The Housing Bureau said that, starting from March 1, 2027, it will adopt a pragmatic and people-oriented approach in enforcing the law against the illegal letting of SDUs with no registration and no recognition to ensure that SDU tenants will not be displaced.

Through its six District Service Teams (DSTs) covering various regions of Hong Kong Island, Kowloon and the New Territories, the bureau will also assist affected households in need in finding alternative accommodations and flexibly co-ordinate other housing resources to provide temporary shelters for them.