Updated at 6.06pm: More than 427,000 households in Hong Kong - or a 1.5 million people - have joined a territory-wide domestic-waste separation scheme, Secretary for the Environment, Transport and Works Sarah Liao Sau-tung revealed on Thursday.

Since its launch in January last year, the Source Separation of Domestic Waste Programme has attracted more than 340 housing estates to join. This amounts to about one fifth of the territory's population, Dr Liao said.

The scheme aims to encourage households to reduce waste disposal by sorting recyclable materials and placing them in bins near their flats.

Dr Liao was speaking at the Forum on Source Separation of Domestic Waste, held by the Environmental Protection Department and Hong Kong Association of Property Management Companies.

Of the participating estates, some 120 have provided waste separation facilities on each floor of the buildings.

Recyclables collected from 60 estates have risen by 50 per cent. This has led to a four per cent reduction of waste disposal, she said.

Dr Liao said a set of guidelines on the setting up of waste separation facilities in residential buildings was published on Thursday.

Hong Kong's environmental authorities expect the domestic waste separation scheme can help save landfill space. This is expected to be full soon.