SINGAPORE - The local arm of conservation group World Wide Fund for Nature (WWF) has written to 19 chief executives in Singapore asking them how much palm oil they use and where it comes from.

The aim, WWF said, is to get the Singapore-based companies to be "transparent" and let their customers know if the palm oil used is sustainable or if it contributes to the haze.

The organisation added that many companies based here are unaware that they are contributing to deforestation "despite five decades of haze and ongoing engagement by WWF".

WWF-Singapore chief executive Elaine Tan said that brands should be or aim to be at 100 per cent certified in sustainable palm oil use today and show consumers how their sustainability policies help to combat the haze.

"Companies that have fallen short of that target should be called to account by their competitors and their customers," she added.

Last week, WWF released a scorecard for palm oil buyers, measuring the commitment of 137 European, United States, Canadian, Australian, Indian and Japanese retailers, manufacturers and food service companies, such as Unilever and Delifrance.

WWF and the Singapore Alliance for Sustainable Palm Oil are currently preparing a similar scorecard for companies in Singapore and the region, which will be released in the middle of next year.