For the first time in its green-building drive, the Building and Construction Authority plans to ask building owners to make their energy performance data public. This will be voluntary and it will begin next year.

The authority also wants to highlight the top 20 per cent of the most energy-efficient buildings.

Mr Tan Chuan-Jin, Acting Minister for Manpower and former Minister of State for National Development, spoke of the move at the International Green Building Conference on Friday at Marina Bay Sands.

Green Mark certification schemes are also being introduced for health-care facilities. The focus is on improving natural ventilation, for example; and for laboratories which concentrate on reducing environmental impact from energy and chemicals use, he added.

The country's building greening drive began in 2005 when it introduced the first Green Mark certification scheme. Today, some 20 per cent of buildings here bear a Green Mark rating for being energy- and water-efficient and having greenery and other measures. Singapore aims to get 80 per cent of all buildings certified by 2030.