SINGAPORE- Six other firms - Ikea Singapore, Prime Supermarket, Sheng Siong, NTUC Unity Healthcare, Watsons Singapore and Dairy Farm International Holdings - have been asked to sign the Singapore Environment Council's (SEC) declaration form.
The form, which has already been sent out to 17 firms, asks businesses to declare their goods free of raw materials from companies being investigated for the forest fires.
So far, 12 of those who received the letters from the initial batch have signed on the dotted line, said the SEC on Wednesday.
Late last month, the National Environment Agency (NEA) began legal action against Singapore-listed APP and four Indonesian firms that it believes to be behind the burning.
"These major supermarkets, pharmacies and furniture retailers operate several outlets from which consumers purchase paper-based products," said the joint statement from the SEC and the Consumers Association of Singapore (Case).
"They are a good starting point for retailers to commit to a green procurement process and for consumers to show their support for brands that have environmentally friendly practices.
"With heightened efforts from both retailers and consumers, SEC and CASE are confident that more companies will join us to promote environmentally friendly conduct," it read.